Use the process of completing the square to fill in the blanks. y = x2 + 8x + 25 y = (x + a0)2 + a1

It would be y=(x+4)²+9.

To complete the square, we divide the value of b, the coefficient of x, by 2 and square it:

(8/2)² = 4² = 16

We would add 16 to this in order to have a perfect square; but we would also need to subtract 16 at the end to keep it equal.  This would give us:

y=(x²+8x+16)+25-16
y = (x+4)² + 9