Answer:
y = 5x2 + 10x - 15
We want this in format y = a(x-h)2 + k
where the vertex will be at (h,k)
y = 5(x2+2x) - 15
Complete the square on x2+2x
y = 5(x2+2x+1) - 15 - 5
We subtract 5 at the end because we are actually adding 5(1) = 5
so we need to remove it also to keep the total equal
y = 5(x+1)2 - 20
The vertex is at (-1,-20)
