here is the problem : 4 - √2-x = √x+6
square each side
(4-√2-x)^2 = (√x+6)^2
foil and simplfy
18-8√2-x bbbb -x = x + 6
pretty much stuck at this point tried adding x and subtracting 18 from left side and put on right but it just turned into a diaster
thanks!