When the equation is squared, you have to foil (8x+5), so it becomes
(8x+5)(8x+5)=63
then you use the distributive property, so it become 64x^2 +40x +40x +25, and you simplify that into 64x^2+80x+25=63
next you subtract 63 from the left, sso it becomes 64x^2+80x-38=0
then you use the quadratic formula -b+/- (root b^2-4ac )/2a to solve for the zeros or x-values