Abbreviated Multiplication Formulas Practice Problems

Master algebraic identities with step-by-step practice problems. Learn square of sum, difference of squares, and cubic formulas through interactive exercises.

📚Master Abbreviated Multiplication Formulas with Targeted Practice
  • Apply (a+b)² = a² + 2ab + b² formula to expand binomial squares
  • Use (a-b)² = a² - 2ab + b² to solve difference of squares problems
  • Master (a+b)(a-b) = a² - b² for sum-difference multiplication
  • Expand cubic expressions using (a+b)³ and (a-b)³ formulas
  • Factor algebraic expressions back into abbreviated forms
  • Solve real-world problems involving quadratic and cubic identities

Understanding Short Multiplication Formulas

Complete explanation with examples

What are Abbreviated Multiplication Formulas?

Abbreviated multiplication formulas, also known as algebraic identities, are shortcuts that simplify the process of expanding and factoring expressions. These formulas save time and reduce the steps required for complex calculations. Abbreviated multiplication formulas will be used throughout our math studies, from elementary school to high school. In many cases, we will need to know how to expand or add these equations to arrive at the solution to various math exercises.

Abbreviated Multiplication Formulas for 2nd degree

Here are the basic formulas for abbreviated multiplication:

The square of the sum:
(X+Y)2=X2+2XY+Y2(X + Y)^2=X^2+ 2XY + Y^2

The squared difference:

(XY)2=X22XY+Y2(X - Y)^2=X^2 - 2XY + Y^2

The difference of squares:

(X+Y)×(XY)=X2Y2(X + Y)\times (X - Y) = X^2 - Y^2

Visual breakdown of abbreviated multiplication formulas: (a+b)² = a² + 2ab + b² and (a−b)² = a² − 2ab + b², with color-coded area models representing the expansion of binomials


Abbreviated Multiplication Formulas for 3rd degree

Abbreviated multiplication formulas for 3rd-degree expressions, also known as cubic identities, build upon the concepts of the 2nd-degree formulas we’ve already covered. The key difference is the adjustment for working with cubic (3rd-degree) terms instead of quadratic (2nd-degree) terms. These formulas simplify complex cubic expressions, breaking them into manageable parts to make calculations faster and more efficient. They are particularly useful in solving problems involving volumes of cubes and other 3D shapes or in advanced mathematics, such as polynomial factoring and equation solving.

Here are two of the most common abbreviated multiplication formulas for 3rd-degree expressions:

Cube of a Sum

(a+b)3=a3+3a2b+3ab2+b3(a+b)^3=a^3+3a^2 b+3ab^2+b^3

Cube of a Difference

​​​​​​​(ab)3=a33a2b+3ab2b3​​​​​​​(a-b)^3=a^3-3a^2 b+3ab^2-b^3


Abbreviated Multiplication Formulas Verification and Examples

We will test the shortcut multiplication formulas by expanding the parentheses.

Square of a Sum:

(X+Y)2=(X+Y)×(X+Y)=(X + Y)^2 = (X + Y)\times (X+Y) =

X2+XY+YX+Y2=X^2 + XY + YX + Y^2=

Since: XY=YXXY = YX

X2+2XY+Y2X^2 + 2XY + Y^2

Example:

(x+3)2 (x+3)^2

(x+3)2=x2+2(x)(3)+32=x2+6x+9 (x+3)^2=x^2+2(x)(3)+3^2=x^2+6x+9


Square of a Difference:

(XY)2=(XY)×(XY)=(X - Y)^2 = (X - Y)\times (X-Y) =

X2XYYX+Y2=X^2 - XY - YX + Y^2=

Since:XY=YX XY = YX

X22XY+Y2X^2 - 2XY + Y^2

Example:

(x4)2 (x−4)^2

(x4)2=x22(x)(4)+42=x28x+16 (x−4)^2=x^2−2(x)(4)+4^2=x^2−8x+16


Product of a Sum and a Difference:

(X+Y)×(XY)=(X + Y)\times (X-Y) =

X2XY+YXY2=X^2 - XY + YX - Y^2=

Since: XY=YX XY = YX

XY+YX=0 - XY + YX = 0

X2Y2X^2 - Y^2

Example:

(x+5)(x5) (x+5)(x−5)

(x+5)(x5)=x252=x225 (x+5)(x−5)=x^2−5^2=x^2−25


Using Abbreviated Multiplication Formulas to Shift the Expression Both Ways

It’s important to remember that these formulas are not one-sided; you can use them to switch between different forms of an expression as needed. For example, you can use the formula:

(X+Y)2=X2+2XY+Y2(X + Y)^2=X^2+ 2XY + Y^2

to expand an expression in parentheses into its expanded form. Conversely, if you encounter an expression like

X2+2XY+Y2X^2+ 2XY + Y^2

you can factor it back into

(X+Y)2(X + Y)^2

This flexibility allows you to work with the representation that is most useful for the problem at hand, whether it’s simplifying, solving, or analyzing the expression. Understanding this two-way functionality is essential for mastering algebraic manipulation.

Detailed explanation

Practice Short Multiplication Formulas

Test your knowledge with 48 quizzes

\( (x^2+4)^2= \)

Examples with solutions for Short Multiplication Formulas

Step-by-step solutions included
Exercise #1

(x26)2= (x^2-6)^2=

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Identify a and b in the expression (x26)2 (x^2 - 6)^2 .
  • Step 2: Apply the square of a difference formula.
  • Step 3: Simplify the resulting expression.

Now, let's work through each step:
Step 1: The expression is (x26)2 (x^2 - 6)^2 . Here, a=x2 a = x^2 and b=6 b = 6 .
Step 2: Apply the binomial formula: (ab)2=a22ab+b2 (a - b)^2 = a^2 - 2ab + b^2 .
Step 3:
1. Calculate a2 a^2 :
a2=(x2)2=x4 a^2 = (x^2)^2 = x^4 .
2. Calculate 2ab 2ab :
2ab=2(x2)(6)=12x2 2ab = 2(x^2)(6) = 12x^2 .
3. Calculate b2 b^2 :
b2=62=36 b^2 = 6^2 = 36 .
4. Substitute these back into the formula:
(x26)2=x412x2+36(x^2 - 6)^2 = x^4 - 12x^2 + 36.

Therefore, the expanded expression is x412x2+36 x^4 - 12x^2 + 36 .

Answer:

x412x2+36 x^4-12x^2+36

Video Solution
Exercise #2

Rewrite the following expression as an addition and as a multiplication:

(3xy)2 (3x-y)^2

Step-by-Step Solution

To solve this problem, let's start by identifying the parts of the binomial:

  • The expression (3xy)2(3x-y)^2 represents a binomial squared.
  • We recognize it has the form (ab)2(a-b)^2 where a=3xa = 3x and b=yb = y.
  • Using the formula for the square of a difference: (ab)2=a22ab+b2(a-b)^2 = a^2 - 2ab + b^2, we find the expanded form.

Let's apply the formula:

Step 1: Expand (3xy)2(3x-y)^2 using the formula:
(3xy)2=(3x)22(3x)(y)+y2(3x-y)^2 = (3x)^2 - 2(3x)(y) + y^2

Step 2: Calculate each part:
(3x)2=9x2(3x)^2 = 9x^2
2(3x)(y)=6xy-2(3x)(y) = -6xy
y2y^2 stays as y2y^2

Step 3: Combine these results to get the addition form:
9x26xy+y29x^2 - 6xy + y^2

The expression in multiplication form, as provided, is just repeating the factors:
(3xy)(3xy)(3x-y)(3x-y)

Therefore, the expression rewritten as addition is 9x26xy+y29x^2 - 6xy + y^2 and as multiplication (3xy)(3xy)(3x-y)(3x-y).

Answer:

9x26xy+y2 9x^2-6xy+y^2

(3xy)(3xy) (3x-y)(3x-y)

Video Solution
Exercise #3

(4b3)(4b3) (4b-3)(4b-3)

Rewrite the above expression as an exponential summation expression:

Step-by-Step Solution

To solve this problem, we will apply the square of a binomial formula.

The given expression is (4b3)(4b3)(4b-3)(4b-3). We recognize this as the square of a binomial, which can be rewritten as (4b3)2(4b-3)^2. To expand this expression, we use the formula:

(ab)2=a22ab+b2(a-b)^2 = a^2 - 2ab + b^2

In our expression, a=4ba = 4b and b=3b = 3. Let's apply the formula:

  • Calculate a2a^2:
    a2=(4b)2=16b2a^2 = (4b)^2 = 16b^2
  • Calculate 2ab-2ab:
    2ab=2(4b)(3)=24b-2ab = -2(4b)(3) = -24b
  • Calculate b2b^2:
    b2=(3)2=9b^2 = (3)^2 = 9

Putting it all together, we have:

(4b3)2=16b224b+9(4b-3)^2 = 16b^2 - 24b + 9

Therefore, the exponential summation expression is (4b3)2(4b-3)^2, with the expanded form:

16b224b+916b^2 - 24b + 9

This matches choice 3, confirming our solution.

Answer:

(4b3)2 (4b-3)^2

16b224b+9 16b^2-24b+9

Video Solution
Exercise #4

Declares the given expression as a sum

(7b3x)2 (7b-3x)^2

Step-by-Step Solution

To solve for (7b3x)2(7b - 3x)^2 as a sum, we'll follow these steps:

  • Step 1: Identify the given expression and apply the formula for the square of a difference:
    (ab)2=a22ab+b2(a - b)^2 = a^2 - 2ab + b^2 where a=7ba = 7b and b=3xb = 3x.
  • Step 2: Expand each term:
    • a2=(7b)2=49b2a^2 = (7b)^2 = 49b^2
    • 2ab=2×7b×3x=42bx-2ab = -2 \times 7b \times 3x = -42bx
    • b2=(3x)2=9x2b^2 = (3x)^2 = 9x^2
  • Step 3: Combine all terms to form the sum:
    (7b3x)2=49b242bx+9x2 (7b - 3x)^2 = 49b^2 - 42bx + 9x^2 .

Therefore, the solution to the problem is (7b3x)2=49b242bx+9x2(7b - 3x)^2 = 49b^2 - 42bx + 9x^2.

Hence, the correct answer choice is: 49b242bx+9x2 49b^2 - 42bx + 9x^2

Answer:

49b242bx+9x2 49b^2-42bx+9x^2

Video Solution
Exercise #5

(xx2)2= (x-x^2)^2=

Step-by-Step Solution

To solve the expression (xx2)2(x-x^2)^2, we will use the square of a binomial formula (ab)2=a22ab+b2(a-b)^2 = a^2 - 2ab + b^2.

Let's identify aa and bb in our expression:

  • Here, a=xa = x and b=x2b = x^2.

Applying the formula:

(xx2)2=(x)22(x)(x2)+(x2)2(x - x^2)^2 = (x)^2 - 2(x)(x^2) + (x^2)^2

Calculating each part, we get:

  • (x)2=x2(x)^2 = x^2
  • 2(x)(x2)=2x3-2(x)(x^2) = -2x^3
  • (x2)2=x4(x^2)^2 = x^4

Combining these results, the expression simplifies to:

x42x3+x2x^4 - 2x^3 + x^2

Therefore, the expanded form of (xx2)2(x-x^2)^2 is x42x3+x2\boxed{x^4 - 2x^3 + x^2}.

Answer:

x42x3+x2 x^4-2x^3+x^2

Video Solution

Frequently Asked Questions

What are abbreviated multiplication formulas and why are they important?

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Abbreviated multiplication formulas, also known as algebraic identities, are shortcuts that simplify expanding and factoring expressions. They save time in calculations and are essential for solving complex algebraic problems throughout middle school, high school, and beyond.

How do I remember the difference between (a+b)² and (a-b)² formulas?

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The key difference is in the middle term: (a+b)² = a² + 2ab + b² has a positive middle term, while (a-b)² = a² - 2ab + b² has a negative middle term. Remember that the sign of the middle term matches the sign in the original expression.

When should I use the difference of squares formula (a+b)(a-b) = a² - b²?

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Use this formula when you see the product of two binomials where one is a sum and the other is a difference of the same terms. It's particularly useful for factoring expressions like x² - 9 = (x+3)(x-3) or simplifying complex fractions.

What are the most common mistakes students make with abbreviated multiplication formulas?

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Common mistakes include: 1) Forgetting the middle term coefficient (2ab), 2) Getting signs wrong in the difference formula, 3) Not recognizing when to apply the formulas, 4) Mixing up expansion and factoring directions.

How do cubic formulas (a+b)³ and (a-b)³ differ from quadratic ones?

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Cubic formulas have four terms instead of three and involve higher powers. (a+b)³ = a³ + 3a²b + 3ab² + b³ follows a pattern with coefficients 1, 3, 3, 1, while (a-b)³ alternates signs. The coefficients come from Pascal's triangle.

Can I use abbreviated multiplication formulas with numbers and variables together?

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Yes! These formulas work with pure numbers (like (5+3)²), pure variables (like (x+y)²), or combinations (like (x+4)²). The key is identifying the pattern regardless of whether you're working with numbers, variables, or both.

How do I factor expressions back into abbreviated forms?

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Look for patterns that match the expanded formulas. For example, if you see x² + 6x + 9, recognize it as a perfect square trinomial (x+3)² because it fits the pattern a² + 2ab + b² where a=x and b=3.

What real-world applications use abbreviated multiplication formulas?

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These formulas appear in geometry (calculating areas and volumes), physics (motion equations), engineering (structural calculations), and economics (profit/loss models). They're fundamental tools for any field requiring mathematical modeling.

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