Question

What are the zeros of f(x)=2x^3+5x^2-2x-5, if one of the zeros is 1?

Answer 1

x = -5/2, -1, 1

Explanation:

Step 1: Factor

• 2x³ + 5x² - 2x - 5
• (2x + 5)x² - 2x - 5
• (2x + 5)(x - 1)(x + 1)

Step 2: Replace y with 0

"f(x)" is the same as "y = "

• 0 = (2x + 5)(x - 1)(x + 1)
• Case 1: (5 + 2x) = 0

• 5 + 2x = 0
• 2x = -5
• x = -5/2

1. Case 2: (x - 1) = 0

• x - 1 = 0
• x = 1

1. Case 3: (x + 1) = 0

• x + 1 = 0
• x = -1

-Chetan K