Answer:
16
Explanation:
Given the expression
x² — 8x + 7 = 10
To complete the square we need to add the half of the square of coefficient of x to both sides to complete the expression.
The coefficient of x is -8
Half of 8 = 1/2(-8) = -4
The square of 4 = (-4)^2 = 16
Hence the value that must be added to both sides to complete the square is 16