find the x intercepts of the parabola with vertex (1,245) and y-intercept of (0,240) write your answer in the format (x1, y1) (x2, y2) if necessary round to the nearest hundredth

Respuesta :

Begin with standard form

y=a(x-h)^2+k

a=y-k/(x-h)^2

a=240-245/(0-1)^2

a=-5/1

a=-5

Solve the standard form equation for the two x intercepts
Let y=0, and just solve for the value of x.

y=-5(x-1)^2+245

-5(x-1)^2=-245

(x-1)^2=-245/(-5)

(x-1)^2=49

x-1=0+-7

x=1+-7

Either x=-6, or x=8

(-6,0) and (8,0)