Examples with solutions for Applying Combined Exponents Rules: Factoring Out the Greatest Common Factor (GCF)

Exercise #1

Extract the common factor:

4x3+8x4= 4x^3+8x^4=

Video Solution

Step-by-Step Solution

First, we use the power law to multiply terms with identical bases:

aman=am+n a^m\cdot a^n=a^{m+n} It is necessary to keep in mind that:

x4=x3x x^4=x^3\cdot x Next, we return to the problem and extract the greatest common factor for the numbers separately and for the letters separately,

For the numbers, the greatest common factor is

4 4 and for the letters it is:

x3 x^3 and therefore for the extraction

4x3 4x^3 outside the parenthesis

We obtain the expression:

4x3+8x4=4x3(1+2x) 4x^3+8x^4=4x^3(1+2x) To determine what the expression inside the parentheses is, we use the power law, our knowledge of the multiplication table, and the answer to the question: "How many times do we multiply the common factor that we took out of the parenthesis to obtain each of the terms of the original expression that we factored?

Therefore, the correct answer is: a.

It is always recommended to review again and check that you get each and every one of the terms of the expression that is factored when opening the parentheses (through the distributive property), this can be done in the margin, on a piece of scrap paper, or by marking the factor we removed and each and every one of the terms inside the parenthesis, etc.

Answer

4x3(1+2x) 4x^3(1+2x)

Exercise #2

Factor the following expression:

2a5+8a6+4a3 2a^5+8a^6+4a^3

Video Solution

Step-by-Step Solution

We will factorize by extracting the largest common factor. In the given expression, there are the following terms:

2a5,8a6,4a3 2a^5,\hspace{4pt}8a^6,\hspace{4pt}4a^3

We'll start with the letters, using the law of exponents for multiplication between terms with identical bases, but in reverse order:

bm+n=bmbn b^{m+n} =b^m\cdot b^n

to understand that:

a6=a3a3a5=a3a2 a^6=a^3\cdot a^3\\ a^5=a^3\cdot a^2

and we'll note that the highest power of a a that can be extracted as a common factor for all three terms is the power of 3, meaning: a3 a^3 ,

we'll continue and extract the largest common factor for the numbers 2,4,8, which is clearly the number 2 since it is a prime number, therefore we'll conclude and extract the common factor: 2a3 2a^3

We'll apply this to the given expression and extract a common factor:

2a5+8a6+4a3=2a3(a2+4a4+2) 2a^5+8a^6+4a^3 =2a^3(a^2+4a^4+2)

where after extracting the common factor outside the parentheses, we'll look at each term before extracting the common factor separately, asking the question: "By how much did we multiply the common factor to get the current term?" and we'll fill in the missing parts inside the parentheses while making sure that the sign of the term we completed inside the parentheses when multiplied by the sign of the term we extracted outside the parentheses gives us the sign of the original term, it is recommended to verify that the factorization is correct by opening the parentheses, performing the multiplications and confirming that we indeed get the expression before factorization.

Therefore the correct answer is answer A.

Answer

a3(25a2+8a3+4) a^3(25a^2+8a^3+4)

Exercise #3

Solve the following by removing a common factor:

6x69x4=0 6x^6-9x^4=0

Video Solution

Step-by-Step Solution

First, we take out the smallest power

6x69x4= 6x^6-9x^4=

6x4(x21.5)=0 6x^4\left(x^2-1.5\right)=0

If possible, we reduce the numbers by a common factor

Finally, we will compare the two sections with: 0 0

6x4=0 6x^4=0

We divide by: 6x3 6x^3

x=0 x=0

x21.5=0 x^2-1.5=0

x2=1.5 x^2=1.5

x=±32 x=\pm\sqrt{\frac{3}{2}}

Answer

x=0,x=±32 x=0,x=\pm\sqrt{\frac{3}{2}}