Examples with solutions for Extracting Square Roots: Applying the formula

Exercise #1

Solve the following exercise:

2x28=x2+4 2x^2-8=x^2+4

Video Solution

Step-by-Step Solution

First, we move the terms to one side equal to 0.

2x2x284=0 2x^2-x^2-8-4=0

We simplify :

x212=0 x^2-12=0

We use the shortcut multiplication formula to solve:

x2(12)2=0 x^2-(\sqrt{12})^2=0

(x12)(x+12)=0 (x-\sqrt{12})(x+\sqrt{12})=0

x=±12 x=\pm\sqrt{12}

Answer

±12 ±\sqrt{12}

Exercise #2

Solve the following exercise:

x220=5 x^2-20=5

Video Solution

Step-by-Step Solution

To solve this quadratic equation x220=5 x^2 - 20 = 5 , we will follow these steps:

  • Step 1: First, add 20 to both sides of the equation to isolate the x2 x^2 term:

x220+20=5+20 x^2 - 20 + 20 = 5 + 20

This simplifies to:

x2=25 x^2 = 25

  • Step 2: Next, take the square root of both sides to solve for x x :

x=±25 x = \pm \sqrt{25}

x=±5 x = \pm 5

Therefore, the solutions to the equation are:

x=5 x = 5 and x=5 x = -5

Thus, the correct answer choice is:

  • ±5 \pm 5 from the provided options.

The correct solution to the problem is ±5 \pm 5 .

Answer

±5

Exercise #3

Solve for X:

xx=49 x\cdot x=49

Video Solution

Step-by-Step Solution

We first rearrange and then set the equations to equal zero.

x249=0 x^2-49=0

x272=0 x^2-7^2=0

We use the abbreviated multiplication formula:

(x7)(x+7)=0 (x-7)(x+7)=0

x=±7 x=\pm7

Answer

±7

Exercise #4

Solve the following:

x2+x23=x2+6 x^2+x^2-3=x^2+6

Video Solution

Step-by-Step Solution

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

  • Simplify the given equation.
  • Solve for x2 x^2 and find x x .

First, let's simplify the equation:

x2+x23=x2+6 x^2 + x^2 - 3 = x^2 + 6 .

Combine like terms on the left side:

2x23=x2+6 2x^2 - 3 = x^2 + 6 .

Subtract x2 x^2 from both sides to isolate one of the x x terms:

2x2x23=6 2x^2 - x^2 - 3 = 6 .

This simplifies to:

x23=6 x^2 - 3 = 6 .

Next, add 3 to both sides to solve for x2 x^2 :

x2=9 x^2 = 9 .

To find x x , take the square root of both sides:

x=±9 x = \pm\sqrt{9} .

This results in:

x=±3 x = \pm3 .

Therefore, the solution to the problem is ±3\pm3.

Answer

±3

Exercise #5

Solve the following equation:

4x2+8+2x=x+12+x 4x^2+8+2x=x+12+x

Video Solution

Step-by-Step Solution

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

  • Step 1: Simplify both sides of the equation.
  • Step 2: Rearrange terms to form a quadratic equation.
  • Step 3: Solve the quadratic equation using an appropriate method, such as factoring or applying the quadratic formula.

Now, let's work through each step:

Step 1: Simplify both sides of the equation:

4x2+8+2x=x+12+x 4x^2 + 8 + 2x = x + 12 + x

The right-hand side can be simplified:

x+x+12=2x+12 x + x + 12 = 2x + 12

This yields the equation:

4x2+8+2x=2x+12 4x^2 + 8 + 2x = 2x + 12

Step 2: Rearrange the terms to form a quadratic equation. Subtract 2x+12 2x + 12 from both sides:

4x2+8+2x2x12=0 4x^2 + 8 + 2x - 2x - 12 = 0

Combining like terms gives:

4x24=0 4x^2 - 4 = 0

Step 3: Solve the resulting quadratic equation:

First, we add 4 to both sides:

4x2=4 4x^2 = 4

Next, divide both sides by 4:

x2=1 x^2 = 1

Now, apply the square root to both sides:

x=±1 x = \pm 1

Therefore, the solutions to the quadratic equation are

x=±1 x = \pm 1 .

The correct answer is choice 2: ±1.

Answer

±1

Exercise #6

Solve the following equation:


2x28=x2+4 2x^2-8=x^2+4

Video Solution

Step-by-Step Solution

Let's solve the equation step-by-step:

  • Step 1: Rearrange the equation.

We start with the given equation:

2x28=x2+42x^2 - 8 = x^2 + 4

Subtract x2+4x^2 + 4 from both sides to get:

2x28x24=02x^2 - 8 - x^2 - 4 = 0

  • Step 2: Simplify the equation.

Combine the like terms:

(2x2x2)84=0(2x^2 - x^2) - 8 - 4 = 0

This simplifies to:

x212=0x^2 - 12 = 0

  • Step 3: Solve for xx.

Add 12 to both sides:

x2=12x^2 = 12

Now take the square root of both sides:

x=±12x = \pm \sqrt{12}

Given the choices, the correct answer is ±12\pm \sqrt{12}.

Answer

±12 ±\sqrt{12}

Exercise #7

Solve the following equation:

x216=x+4 x^2-16=x+4

Video Solution

Step-by-Step Solution

Please note that the equation can be arranged differently:

x²-16 = x +4

x² - 4² = x +4

We will first factor a trinomial for the section on the left

(x-4)(x+4) = x+4

We will then divide everything by x+4

(x-4)(x+4) / x+4 = x+4 / x+4

x-4 = 1

x = 5

Answer

5

Exercise #8

Solve the following exercise

x3x+7=2x2+9 x\cdot3\cdot x+7=2x^2+9

Video Solution

Step-by-Step Solution

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

  • Simplify the given expression.
  • Rearrange into standard quadratic form.
  • Solve using applicable method.

Let's begin the process:
1. Simplify the left-hand side: x3x+7=3x2+7 x \cdot 3 \cdot x + 7 = 3x^2 + 7 .

2. Set up the equation by balancing: 3x2+7=2x2+9 3x^2 + 7 = 2x^2 + 9 .

3. Rearrange the terms to form a quadratic equation: 3x22x2+79=0 3x^2 - 2x^2 + 7 - 9 = 0 .

This simplifies to: x22=0 x^2 - 2 = 0 .

4. Solve for x x :
By adding 2 to both sides, we have: x2=2 x^2 = 2 .
Take the square root of both sides: x=±2 x = \pm\sqrt{2} .

Therefore, the solution to the problem is ±2 \pm\sqrt{2} .

Answer

±2 ±\sqrt{2}

Exercise #9

Solve the following equation:

x236=6x36 x^2-36=6x-36

Video Solution

Step-by-Step Solution

To solve the equation x236=6x36 x^2 - 36 = 6x - 36 , follow these steps:

  • Simplify the equation by subtracting 6x and 36 from both sides to get: x26x=0 x^2 - 6x = 0 .
  • Notice that the equation can be factored as it has a common factor: x(x6)=0 x(x - 6) = 0 .
  • According to the zero product property, set each factor equal to zero: x=0 x = 0 or x6=0 x - 6 = 0 .
  • Solve each resulting equation: x=0 x = 0 and x=6 x = 6 .

Therefore, the solutions to the quadratic equation x236=6x36 x^2 - 36 = 6x - 36 are x=0 x = 0 or x=6 x = 6 .

Answer

0 or 6 0~or~6