Question

X2 − 15x = −50 A) x = 3, x = 5 B) x = 5, x = 10 C) x = 3, x = −5 D) x = −5, x = −10

Answer 1

x = 10 or x = 5 thus: B is the answer

Explanation:

Solve for x over the real numbers:

x^2 - 15 x = -50

Add 225/4 to both sides:

x^2 - 15 x + 225/4 = 25/4

Write the left-hand side as a square:

(x - 15/2)^2 = 25/4

Take the square root of both sides:

x - 15/2 = 5/2 or x - 15/2 = -5/2

Add 15/2 to both sides:

x = 10 or x - 15/2 = -5/2

Add 15/2 to both sides:

Answer: x = 10 or x = 5