Question

Pls help me on this i don't know what to do ​

Answer 1

D.

Explanation:

Standard Form (Quadratic):
`y=ax^2+bx+c`

Vertex Form (Quadratic):
`y=a(x-h)^2+k`

Intercept Form (Quadratic):
`y=a(x-p)(x-q)`

p,q are x-intercepts

x-intercepts given in graph: -2,4

`y=a[x-(-2)](x-4)`

eqn 1:
`y=a(x+2)(x-4)`

Plug in the given point to find 'a' : (3,-5)

`-5=a(3+2)(3-4)`

`-5=a(5)(-1)`

`1=a`

Substitute 'a' in to eqn 1.

`y=1(x+2)(x-4)`

eqn 2:
`y=(x+2)(x-4)`

Expand eqn 2. (can use FOIL)

`y=x^2-2x-8`