Question

A student performed the following steps to find the solution to the question x^2 - 2x - 15 = 0. Where did the student go wrong?

Step 1: Factor the polynomial into (x + 3) and (x - 5)
Step 2: x + 3 = 0 and x - 5 = 0
Step 3: x = 3 and x = -5

A. In step 2

B. The student did not make any mistakes, the solution is correct

C. In step 1

D. In step 3

Answer 1

D In step 3

Explanation:

Given polynomial: x² - 2x - 15 = 0

Step 1: factor the polynomial ⇒ (x + 3)(x - 5) = 0

Step 2: x + 3 = 0 and x - 5 = 0

Step 3: x = -3 and x = 5

x - 5 = 0

Add 5 to both sides:

⇒ x - 5 + 5 = 0 + 5

⇒ x = 5