Tìm x biết: a) (2x + 1)^2 - 4(x + 2)^2 = 9; b) (3x - 1)^2(x + 3)^2 + 11(x + 1)(x - 1) = 6

tìm x
a) (2x+1)^2-4(x+2)^2=9
b) (3x-1)^2(x+3)^2+11(x+1)(x-1)=6
c) 16x^2-(4x-5)^2=15
d) (2x+1)(1-2x)+(1-2x)^2=18