Question

What are the x-intercepts of the graph of the function f(x) = x2 + 5x − 36?

(−4, 0) and (9, 0)
(4, 0) and (−9, 0)
(−3, 0) and (12, 0)
(3, 0) and (−12, 0)

Answer 1

B, is correct i just took the edgnuity unit test

Answer 2

Answer: Second option: (4,0) and (-9,0)

f(x)=x^2+5x-36

The x-intercepts of the graph of a function f(x) are the values of the variable x that makes f(x)=y equal to zero. To find these values we only have to equal f(x)=y to zero:
f(x)=y=0
x^2+5x-36=0

Factoring the polynomial:
(x+9)(x-4)=0

Using that if a b=0, then: a=0 or b=0
with a=x+9 and b=x-4

x+9=0 or x-4=0

Solving for x:
x+9-9=0-9 or x-4+4=0+4
x=-9 or x=4

Then the x-intercepts are the poitns (x,y)=(x,0):
(4,0) and (-9,0)