Factoring a Difference of Squares: Solve x^2 - 49 = (x-_—)(x+_—)

Question

Fill in the missing element to obtain a true expression:

x249=(x)(x+) x^2-49=(x-_—)\cdot(x+_—)

Video Solution

Step-by-Step Solution

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

  • Step 1: Recognize that 49=72 49 = 7^2 .
  • Step 2: Apply the difference of squares formula a2b2=(ab)(a+b) a^2 - b^2 = (a - b)(a + b) .
  • Step 3: Compare the equation to the form and determine the blanks as 7 7 .

Now, let's work through each step:

Step 1: The given expression is x249 x^2 - 49 . Observe that 49 is a perfect square, written as 72 7^2 .

Step 2: According to the difference of squares formula, x249 x^2 - 49 can be rewritten as x272 x^2 - 7^2 , which equals (x7)(x+7) (x - 7)(x + 7) .

Step 3: Plugging in our values, we know the expression matches the form (x_)(x+_) (x - \_)\cdot(x + \_) , with 7 7 being the missing number.

Therefore, the solution to the problem is 7, which corresponds to choice 2.

Answer

7