Solve (x-3)(x+3) = (x-9)(x+9)+x+5: Factored Form Equation Challenge

Question

Solve the following equation:

(x3)(x+3)=(x9)(x+9)+x+5 (x-3)(x+3)=(x-9)(x+9)+x+5

Video Solution

Solution Steps

00:00 Solve
00:05 Let's use the shortened multiplication formulas
00:25 Calculate 9 squared
00:31 Simplify what we can
00:38 Group terms
00:44 Isolate X
00:52 And this is the solution to the question

Step-by-Step Solution

To solve this problem, we'll use the following steps:

  • Step 1: Recognize and apply the difference of squares formula to both sides of the equation.
  • Step 2: Simplify the equation.
  • Step 3: Solve for xx.

Let's go through the solution step-by-step:

Step 1: Simplify each side using the difference of squares formula.

The left-hand side is (x3)(x+3)=x232=x29(x-3)(x+3) = x^2 - 3^2 = x^2 - 9.

The right-hand side is (x9)(x+9)+x+5=(x292)+x+5=x281+x+5(x-9)(x+9) + x + 5 = (x^2 - 9^2) + x + 5 = x^2 - 81 + x + 5.

Step 2: Set the simplified expressions equal to each other.

x29=x281+x+5x^2 - 9 = x^2 - 81 + x + 5

Step 3: Subtract x2x^2 from both sides to eliminate the quadratic term, simplifying the equation:

9=81+x+5-9 = -81 + x + 5

Simplify by combining like terms on the right-hand side:

9=x76-9 = x - 76

Add 76 to both sides to solve for xx:

9+76=x-9 + 76 = x

x=67x = 67

Therefore, the solution to the equation is x=67\mathbf{x = 67}.

Answer

67