Examples with solutions for Difference of squares: Identify the greater value

Exercise #1

Solve each equation separately and find which x is the largest.

  1. (x+4)(x4)=0 (\sqrt{x}+4)(\sqrt{x}-4)=0

  2. x=4 \sqrt{x}=4

Video Solution

Step-by-Step Solution

To solve these equations, we'll follow these steps:

  • Step 1: Solve (x+4)(x4)=0 (\sqrt{x}+4)(\sqrt{x}-4)=0
  • Step 2: Solve x=4 \sqrt{x}=4
  • Step 3: Compare both solutions to find the largest value of x x

Let's work through each step:

Step 1: For the equation (x+4)(x4)=0 (\sqrt{x}+4)(\sqrt{x}-4)=0 , note that it is in the form of a difference of squares: a2b2=(ab)(a+b)=0 a^2 - b^2 = (a-b)(a+b) = 0 . Here, a=x a = \sqrt{x} and b=4 b = 4 , giving:

a2b2=(x)242=x16=0 a^2 - b^2 = (\sqrt{x})^2 - 4^2 = x - 16 = 0

This simplifies to x16=0 x - 16 = 0 , meaning x=16 x = 16 .

Step 2: For the equation x=4 \sqrt{x} = 4 , squaring both sides yields:

(x)2=42 (\sqrt{x})^2 = 4^2 x=16 x = 16

Step 3: Now that both equations result in x=16 x = 16 , there is only one unique solution. Comparing the single value from each equation, x=16 x = 16 is the largest.

Therefore, the largest x x is x=16 x = 16 .

Answer

2=1

Exercise #2

Solve each equation separately and find which x is the largest.

  1. (x+8)(x8)=0 (\sqrt{x}+8)(\sqrt{x}-8)=0

  2. x2100=0 x^2-100=0

Video Solution

Step-by-Step Solution

To solve each equation separately and find the largest value for x x , follow these steps:

  • Step 1: Solve (x+8)(x8)=0 (\sqrt{x}+8)(\sqrt{x}-8)=0 .
  • Step 2: Solve x2100=0 x^2-100=0 .
  • Step 3: Compare the solutions to determine the largest x x .

Now, let's solve each step:

**Step 1**: For the equation (x+8)(x8)=0 (\sqrt{x}+8)(\sqrt{x}-8)=0 , apply the zero-product property:

- x+8=0\sqrt{x}+8=0 or x8=0\sqrt{x}-8=0.
Solving these, we get:
From x+8=0\sqrt{x}+8=0:
x=8\sqrt{x} = -8, which has no real solutions since square roots cannot be negative.
From x8=0\sqrt{x}-8=0:
x=8\sqrt{x} = 8, thus x=82=64x = 8^2 = 64.

**Step 2**: For the equation x2100=0 x^2-100=0 , recognize it as a difference of squares x2102=0 x^2-10^2=0 :

- Factoring gives (x10)(x+10)=0(x-10)(x+10)=0.
Solving these, we find:
x10=0x-10=0, so x=10x=10.
x+10=0x+10=0, so x=10x=-10.

**Step 3**: Compare the solutions of both equations to determine the largest x x :

- From Step 1, the valid solution is x=64x=64. - From Step 2, the valid solutions are x=10x=10 and x=10x=-10.
The largest x x is 6464 from the solutions obtained.

Therefore, the largest solution for x x is x=64 x = 64 .

Answer

1

Exercise #3

Solve each equation separately and find which x is the largest.

  1. 3+x+1756x=18x+44 3+x+17-56x=18x+44

  2. (x2)(x+2)=0 (x-2)(x+2)=0

Video Solution

Step-by-Step Solution

Let's solve each equation step-by-step and find the largest x x .

Equation 1: 3+x+1756x=18x+44 3 + x + 17 - 56x = 18x + 44

This is a linear equation. We will simplify and solve for x x .

  • Combine like terms on the left side: 3+17+x56x=2055x 3 + 17 + x - 56x = 20 - 55x .
  • Equate the simplified expression to the right side: 2055x=18x+44 20 - 55x = 18x + 44 .
  • Move all terms involving x x to one side: 2044=18x+55x 20 - 44 = 18x + 55x .
  • This simplifies to 24=73x -24 = 73x .
  • Solve for x x by dividing both sides by 73: x=2473 x = -\frac{24}{73} .

The solution for x x from the first equation is x=2473 x = -\frac{24}{73} .

Equation 2: (x2)(x+2)=0(x-2)(x+2) = 0

This equation is a difference of squares, (x24)=0(x^2 - 4) = 0.

  • Apply the zero-product property: x2=0 x - 2 = 0 or x+2=0 x + 2 = 0 .
  • Solve each equation: x=2 x = 2 and x=2 x = -2 .

The solutions from the second equation are x=2 x = 2 and x=2 x = -2 .

Conclusion

From both equations, we have the possible values of x x as 2473-\frac{24}{73}, 2-2, and 22.

The largest value among these is 22.

Therefore, the largest x x is 2 2 .

Answer

2