Question

In order to complete the square for the equation below, what value should be added to both sides of the equation?
x2 - 8x + ? = 42 + ?

Answer 1

Answer:

? = 16

Step-by-step explanation:

x2 - 8x + ? = 42 + ?

1. Take the coefficient of the middle term 8x, which is 8 and divide it by 2.  $\frac{8}{2} = -4$. Then square it  $-4^{2} = 16$

2. Take 16 and add it to both sides: $x^2 - 8x + 16 = 42 + 16$

2. Take half of the coefficient 8 that you divided by 2, which is 4 and insert 4 into the equation $(x -4)^2 = 58$

3. ? = 16