Tìm x, y biết: a) x(y + 2) = 1; b) (x + 1)(y - 3) = -2

Tìm x,y biết:
a) x ( y+2 ) = 1
b) ( x+1 ) . ( y-3 ) = -2
c) / x-1 / + / y+2 / = 1
d) x - xy + 5 = 4