[836-(4×200+X)]:[27-(35:7+7)]=2
[836 - (800 + x)] ; [ 27 - (5 + 7)] = 2
[836 - (800 + x)] : [27 - 12] = 2
[836 - (800 - x)] : 15 = 2
836 - (800 - x) = 2 x 15
836 - (800 - x) = 30
800 - x = 836 - 30
800 - x = 806
x = 800 - 806
x = - 6
