174k views
2 votes
HELP ASAP PLEASE!!!

Which equation could be the equation of the graphed parabola?


A
y = -x² - 4x - 5

B
y = x² - 4x + 5

C
y = x² - 4x - 5

HELP ASAP PLEASE!!! Which equation could be the equation of the graphed parabola? A-example-1

1 Answer

6 votes

Answer:

C

y = x² - 4x - 5


Explanation:

looking at the graph it crosses the x axis at 5 and -1

using the zero product property in reverse we can find the equation

subtract the roots from x and set equal to zero

(x-a) (x-b) =0 where a and b are the roots of the quadratic

(x-5) (x--1) = 0

(x-5) (x+1) =0

Foil

first x*x=x^2

outer : x*1=1x

inner: -5*x=-5x

last : -5*1=-5

add these together

x^2 +x-5x-5=0

x^2 -4x-5 =0

now set this equal to y to find points outside the x axis

y = x^2 -4x-5

User Harith
by
6.2k points