## anonymous 4 years ago What value is added to both sides of the equation x2 – 8x = –10 in order to solve by completing the square? a. –8 b. 16 c. –4 d. 4 I think its a, am i right?

1. Mertsj

One half of 8 is 4 and 4 squared is 16 so add 16 to both sides.

2. anonymous

wait what

3. anonymous

what mertsj said, with exactly that reasoning

4. anonymous

forget the number on the right hand side, it is irrelevant

5. anonymous

you have $x^2-\color{red}{8}x$ $\frac{8}{2}=4, 4^2=16$ add 16 to both sides get $(x-4)^2=-10+16=6$

6. anonymous

you should think it in english exactly as mertsj wrote it half of 8 is 4, 4 squared is 16

7. anonymous

oh i see, i guess i understand better with visual. Thanks a ton!

8. anonymous

$x^2+12x=-5$ half of 12 is 6, 6 squared is 36 $(x+6)^2=-5+36$ etc