Bài 1 :

a) \(2.\left(x-1\right)^2-4.\left(3x+x\right)^2+2x.\left(x-5\right)\)

\(2.\left(\left(x-1\right)^2-2\left(3x+x\right)^2+x\left(x-5\right)\right)\)

\(2.\left(\left(x-1\right)^2-2.\left(4x\right)^2+x^2-5x\right)\)

\(2.\left(\left(x-1\right)^2-\left(2^2x\right)^2+x^2-5x\right)\)

\(2.\left(\left(x-1\right)^2-2.2^4x^2+x^2-5x\right)\)

\(2.\left(x-1\right)^2-2^5x^2+x^2-5x\)

\(2.\left(\left(x-1\right)^2-32x^2+x^2-5x\right)\)

\(2.\left(x^2-2x+1-31x^2-5x\right)\)

\(2.\left(-30x^2-7x+1\right)\)

b) \(2.\left(2x+5\right)^2-3\left(4x+1\right)\left(1-4x\right)\)

\(2.\left(4x^2+20x+25\right)-3\left(1+4x\right)\left(1-4x\right)\)

\(8x^2+40x+50-3\left(1-16x^2\right)\)

\(8x^2+40x+50-3+48x^2\)

\(56x^2+40x+47\)

c) \(4\left(x+1\right)^2+\left(2x-1\right)^2-8\left(x-1\right)\left(x+1\right)\)

\(4.\left(x^2+2x+1\right)+4x^2-4x+1-8\left(x^2-1\right)\)

\(4x^2+8x+4+4x^2-4x+1-8x^2+8\)

\(0+4x+13\)

\(4x+13\)