Tìm x ∈ Z biết: -2.(x + 6) + 6(x - 10) = 8

Tìm x ∈ Z biết :
a) -2. (x + 6) + 6 (x - 10) = 8
b) -4.(2x + 9) - (-8x + 3) - (x +13) = 0
c ) 7x. (2 + x ) - 7x . (x + 3 ) =14
d) 2. (5 + 3x ) + x = 31