Examples with solutions for Extracting Square Roots: Solving the equation

Exercise #1

Solve for x x :

4x2+1=0 4x^2+1=0

Video Solution

Step-by-Step Solution

First, we should notice that it is a quadratic equation because there is a quadratic term (meaning raised to the second power).

The first step in solving a quadratic equation is always arranging it in a form where all terms on one side are ordered from highest to lowest power (in descending order from left to right) and 0 on the other side.

Then we can choose whether to solve it using the quadratic formula or by factoring/completing the square.

The equation in the problem is already arranged, so let's proceed with the solving technique:

We'll choose to solve it using the quadratic formula.

Let's recall it first:

The rule states that the roots of an equation in the formax2+bx+c=0 ax^2+bx+c=0 are x1,2=b±b24ac2a x_{1,2}=\frac{-b\pm\sqrt{b^2-4ac}}{2a} .

This formula is called: "The Quadratic Formula"

Let's now solve the problem:

4x2+1=0 4x^2+1=0

First, let's identify the coefficients of the terms:

{a=4b=0c=1 \begin{cases}a=4 \\ b=0 \\ c=1\end{cases}

Note that in the given equation there is no first-power term, so from comparing to the general form:

ax2+bx+c=0 ax^2+bx+c=0

we can conclude that the coefficient b b (which is the coefficient of the first-power term x x in the general form) is 0.

Let's continue and get the equation's solutions (roots) by substituting the coefficients we noted earlier in the quadratic formula:

x1,2=b±b24ac2a=0±0244124 x_{1,2}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}=\frac{0\pm\sqrt{0^2-4\cdot4\cdot1}}{2\cdot4}

Let's continue and calculate the expression under the root and simplify the expression:

x1,2=±168 x_{1,2}=\frac{\pm\sqrt{-16}}{8}

We now have a negative expression under the root and since we cannot extract a real root from a negative number, this equation has no real solutions.

In other words, there is no real value of x x that when substituted in the equation will give a true statement.

Therefore, the correct answer is answer D.

Answer

No solution

Exercise #2

Solve the following equation:

x216=0 x^2-16=0

Video Solution

Answer

x1=4,x2=4 x_1=-4,x_2=4

Exercise #3

Solve the following equation

x225=0 x^2-25=0

Video Solution

Answer

x1=5,x2=5 x_1=5,x_2=-5

Exercise #4

Solve the following equation:

x2+x=0 -x^2+x=0

Video Solution

Answer

x1=0,x2=1 x_1=0,x_2=1

Exercise #5

Solve the following equation:

x21=0 x^2-1=0

Video Solution

Answer

x1=1,x2=1 x_1=1,x_2=-1

Exercise #6

Solve the following equation:

3x212=0 3x^2-12=0

Video Solution

Answer

x1=6,x2=6 x_1=6,x_2=-6

Exercise #7

Solve the following equation:

x2+7x=0 -x^2+7x=0

Video Solution

Answer

x1=0,x2=7 x_1=0,x_2=7

Exercise #8

Solve the following equation:

x2+2x=0 x^2+2x=0

Video Solution

Answer

x1=0,x2=2 x_1=0,x_2=-2

Exercise #9

Solve the following equation:

4x2+8x=0 4x^2+8x=0

Video Solution

Answer

x1=0,x2=2 x_1=0,x_2=-2

Exercise #10

Solve the following equation:

x236=0 x^2-36=0

Video Solution

Answer

x1=6,x2=6 x_1=-6,x_2=6

Exercise #11

Solve the following equation:

2x28=0 2x^2-8=0

Video Solution

Answer

x1=2,x2=2 x_1=2,x_2=-2

Exercise #12

Solve the following equation:

x2+1=0 x^2+1=0

Video Solution

Answer

No solution

Exercise #13

Solve the following equation:

x264=0 x^2-64=0

Video Solution

Answer

x1=8,x2=8 x_1=8,x_2=-8

Exercise #14

Solve the following equation:

2x28=0 2x^2-8=0

Video Solution

Answer

x1=2,x2=2 x_1=-2,x_2=2

Exercise #15

Solve the following equation:

2x2+4x=0 -2x^2+4x=0

Video Solution

Answer

x1=2,x2=0 x_1=2,x_2=0

Exercise #16

Solve the following equation:

3x2+14x=0 3x^2+14x=0

Video Solution

Answer

Answers a + c

Exercise #17

Solve the following equation:

5x225x=0 5x^2-25x=0

Video Solution

Answer

x1=0,x2=5 x_1=0,x_2=5