Question

what must you add to complete the square? x^2+10x=8

Answer 1

25-8=13

Answer 2

oh wait. question probably means you want to write the lhs as a perfect square. half of 10 is 5 and \[5^2=25\] so add 25 to both sides .. sorry

Answer 3

see basically the logic is to bring it to the form (x+b)^2=x^2+b2+2xb, so for getting this factorisation, see appropriately what to add.
observe that the x term has co-efficient 2b and so if u hav a b^2 term u will form the complete square by the formula rite? so u add b^2

Answer 4

if you add 25 to both sides you get
\[x^2+10x+25=33\]or
\[(x+5)^2=33\]