Is my answer correct? ;)

What value is added to both sides of the equation x2 - 8x = -10 in order to solve by completing the square?

Answer: I know it would be 16 if the answer to the problem was -11, but in this case, the answer I got was "-8"

Question

Is my answer correct? ;)

What value is added to both sides of the equation x2 - 8x = -10 in order to solve by completing the square?

Answer: I know it would be 16 if the answer to the problem was -11, but in this case, the answer I got was "-8"

jim_thompson5910 · Answer

what do you mean by "I know it would be 16 if the answer to the problem was -11"

anonymous · Answer

I applied a certain step, and I figured I'd do the opposite for this problem....

jim_thompson5910 · Answer

and what step was that

anonymous · Answer

a^2-2ab+b^2 = (a-b)^2
 a = x
=> 2ab = 8x
=> b = 8x/2x
=> b = 4
=> b^2 = 16
 16 is to be added to both sides of the equation.

jim_thompson5910 · Answer

good, you can also use this shortcut

x coefficient: -8

cut the x coefficient in half: -8/2 = 4

square that last result: 4^2 = 16

anonymous · Answer

thank you

jim_thompson5910 · Answer

yw

anonymous · Answer

that makes it easier, thanks :)