Rút gọn các biểu thức sau:
a/\(\left(3x-1\right)^2-2\left(2-5x\right)^2-2\left(x^2+x-1\right)\left(x-1\right)\)
b/\(\left(3a-1\right)^2+2\left(9a^2-1\right)+\left(3a-1^{ }\right)^2\)
c/\(\left(3x-4^{ }\right)^2+\left(4-x\right)^2-2\left(3x-4\right)\left(x-4\right)\)