Question

Find all of the zeros of f(x) = 5x^2 +40x-100

Answer 1

Answer:

B

Step-by-step explanation:

Given

5x² + 40x - 100

To find the zeros equate to zero, that is

5x² + 40x - 100 = 0 ( divide all terms by 5 )

x² + 8x - 20 = 0

To factor the quadratic

Consider the factors of the constant term (- 20) which sum to give the coefficient of the x- term (+ 8)

The factors are + 10 and - 2, since

10 × - 2 = - 20 and 10 - 2 = + 8, thus

(x + 10)(x - 2) = 0

Equate each factor to zero and solve for x

x + 10 = 0 ⇒ x = - 10

x - 2 = 0 ⇒ x = 2

Zeros are x = - 10 and x = 2 → B

Answer 2

Answer:the answer is B

Step-by-step explanation: