Bài 4:Rút gọn biểu thức
a) \(2x\left(x-5\right)-\left(x-2\right)^2-\left(x+3\right).\left(x-3\right)\)
b) \(\left(x+1\right)^2+3\left(x-5\right).\left(x+5\right)-\left(2x-1\right)^2\)
c) \(2x\left(x-7\right)-\left(x+3\right)\left(x-2\right)-\left(x+4\right)\left(x-4\right)\)
d) \(\left(x+3\right)\left(x-3\right)-\left(x+5\right).\left(x-1\right)-\left(x-4\right)^2\)