Tính: (x + 2y) 2

1. Tính
a) (x + 2y) 2 ; b) (x - 3y)(x + 3y);
c) (5 - x) 2 .
d) (3 - y) 2 
e) (x + 1/2)^2
2.Tìm x,biết
a) (2x + 1) 2 - 4(x + 2) 2 = 9;
b) (x + 3) 2 - (x - 4)( x + 8) = 1;
c) 3(x + 2) 2 + (2x - 1) 2 - 7(x + 3)(x - 3) = 36