Question

Find the vertex, zero(s), and y-intercept of the graph of y = 2x2 + 8x – 90. A. Vertex: (–2,–98); zeros: (–5,0), (9,0) y-intercept: (0,–90) B. Vertex: (2,–98); zeros: (–5,0), (9,0) y-intercept: (0,90) C. Vertex: (2,98); zeros: (5,0), (–9,0) y-intercept: (0,–90) D. Vertex: (–2,–98); zeros: (5,0), (–9,0) y-intercept: (0,–90)

Answer 1

Answer:

vertex is (-2,-98)

zeros are (5,0) (-9,0)

y-intercept is (0,-90)

Step-by-step explanation:

we are given

$y=2x^2+8x-90$

Vertex:

we can use vertex formula

$y=ax^2+bx+c$

$x=-\frac{b}{2a}$

we can compare and find a,b and c

a=2 , b=8 and c=-90

so, we can plug it in formula

$x=-\frac{8}{2\times 2}$

$x=-2$

now, we can find y-value

$y=2(-2)^2+8(-2)-90$

$y=-98$

so, vertex is (-2,-98)

zeros:

we can set y=0

and then we can solve for x

$y=2x^2+8x-90=0$

we can factor it

$2(x-5)(x+9)=0$

$x=5,x=-9$

zeros are

(5,0) (-9,0)

y-intercept:

we can plug x=0 and find y

$y=2(0)^2+8(0)-90$

$y=-90$

So, y-intercept is (0,-90)