Đáp án+Giải thích các bước giải:
Bài 10:
`A = (3x-5) (2x +11) - (2x +3)(3x+7)`
`A = 6x^2 + 33x -10x - 55 - (6x^2 + 14x + 9x +21)`
`A = 6x^2 + 33x - 10x - 55 - 6x^2 + 23x +21`
`A = -76`
`B = (x-5)(2x +3)-2x(x-3)+x+7`
`B = 2x^2 + 3x - 10x - 15 - 2x^2 + 6x + x +7`
`B = 0-8`
`B =-8`
`C = 4(x-6)- x^2(2+3x) + x(5x -4)+ 3x^2(x-1)`
`C = 4x - 24 - 2x^2 - 3x^3 + 5x^2 - 4x + 3x^2 - 3x^2`
`C = -24 +0`
`C = -24`
`D = x(y+z-yz)-y(z+x-zx)+z(y-x)`
`D = xy - xz - xyz - y (z + x - xz) + yz -xz`
`D = xy - xyz - yz - yx + xyz + yz - xz`
`D = 0+0+0+0 =0`