The answer is 9 :) i just did it on paper
1: Subtract 168 from both sides
y-168=8x
2:divide both sides by 8
y-168/8 = x
3: just flip it over
x=168/8
7X3=21 could solve the problem.
= 12*5 + 12*3i - 5*2i - 6i^2 (remember that i^2 = -1) so:-
= 60 +26i - 6*(-1)
= 60 + 26i + 6
= 66 + 26i