Ta có 2x(2x + 1)² - 3x(x + 3)(x - 3) - 4x(x + 1)²

= 2x(4x² + 4x + 1) - 3x(x² - 9) - 4x(x² + 2x + 1) 

= 8x³ + 8x² + 2x - 3x³ + 27x - 4x³ - 8x² - 4x

= 8x³ - 3x³ - 4x³ + 8x² - 8x² + 2x + 27x - 4x

= x³ + 25x 

a oi hinh nhu sai r con +16x² nua co a , anh tinh lai ho e duoc kh

Kiều Trinh Vũ ko có + 16x² nhá vì 8x² - 8x² = 0 nhá 

help voi a

a: \(\left(3x+2\right)^2+4x-3x^2+2\left(5x-2\right)\left(5x+2\right)-75x^2\)

\(=9x^2+12x+4+4x-3x^2+50x^2-8-75x^2\)

\(=-19x^2+16x-4\)

12x²  + 8x - 9x - 6 - 12x² + 30x + 2x -5 + 1= 31x - 10

A) 2x²(1-3x)+6x³

=2x²*(1-3x)+2x²*3x

=2x²*(1-3x+3x)

=2x²

B) (x-y)²+(x+y)²+2(x-y)(x+y)

=2(x²-y²)+x²+2xy+y²+x²-2xy+y²

=2x²-2y²+x²+2xy+y²+x²-2xy+y²

=4x²

\(2x^2\left(x-2\right)-2x\left(x-1\right)\left(x+1\right)=2x^3-4x^2-2x^3+2x=-4x^2+2x=-2x\left(2x-1\right)\)

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

\(=2x^3-4x^2-2x\left(x^2-1\right)\)

\(=2x^3-4x^2-2x^3+2x=-4x^2+2x\)

\(\left(4x-3\right).\left(x-5\right)-2x\left(2x-11\right)\)

=\(4x^2-20x-3x+15-\left(4x^2-22x\right)\)

\(=4x^2-20x-3x+15-4x^2+22x\)

\(=-x+15\)

=\(-19\frac{1}{4}\)

\((2x-1)(x-2)=2x^2-4x-x+2=2x^2-5x+2\)