15a =6a - 90
Move all the numbers with variables to one side
15a - (6a) = 6a -(6a) -90
9a = -90
9a/9 = -90/9
a = -9
Hope this helps
For x intercepts, plug in 0 for y.
0 = (x^2) - 2x - 35
*factoring* = (x-7)(x+5)
x intercepts = 7,-5
As for the vertex, you can use the equation -b/2a for the x-coordinate of the vertex
so,
x = -b/2a = -(-2)/2 = 1
then just find the y value by plugging it back in to the equation.
y = ((1)^2) - 2(1) - 35
= -36
so, vertex is at (1,-36)
