Question

Which is a solution to the equation?

(x -2)(x+5)=18


x=-10

x=-7

x=-4

x=-2

Answer 1

B, x = -7

Explanation:

Answer 2

x = -7

Explanation:

Steps of solution:

• (x -2)(x+5)=18
• x² + 5x - 2x -10 = 18
• x² + 3x - 10 - 18 = 0
• x² + 3x -28 = 0
• x² - 4x + 7x - 28 = 0
• x(x - 4) + 7(x - 4) = 0
• (x - 4)(x+7) = 0
• x - 4 = 0 ⇒ x = 4
• x + 7 = 0 ⇒ x = -7

The roots are:

• 4 and - 7

Correct answer option is:

• -7