Answer:
Step-by-step explanation:
bit lengthy but....
we know vertex is equal (h,k)
h=x . k=y
the vertex formula is f(x)= a(x-h)^2+k
lets plug in vertex... a(x+7)^2+45
we need to solve for (a) in order to make sure this will pass thru the coordinate (0,-200) and then from there we can get our x int.
the way we solve for a is to set the equation equal to the y int (-200)
f(x)=a(x+7)^2+45=-200
lets set x=0 because we already set y=-200
a(0+7)^2+45=-200
a(7)^2+45=-200
49a+45=-200
49a=-245
a=-5
Now lets rewrite the vertex form formula with a leading coefficient of -5
-5(x+7)^2+45
now graph this formula verify that it does indeed intersect (0.-200)
then check the table for your zeros or x int you will see that they are
(-10,0) and (-4,0)
or x+10=0 and x+4=0
