Đáp án+Giải thích các bước giải:
`a)2x(x-1)+3(5x)`
`=2x^2-2x+15x`
`=2x^2+13x`
`b)(2x-3)(x+5)`
`=2x^2+10x-3x-15`
`=2x^2+7x-15`
`c)4x^2(x-3)+5x(x+2)`
`=4x^3-12x^2+5x^2+10x`
`=4x^3-7x^2+10x`
`d)4(x+3)-5(x+7)`
`=4x+12-5x-35`
`=-x-23`
`e)4(x-2x^2)+3x(x-5)`
`=4x-8x^2+3x^2-15x`
`=-5x^2-11x`
`f)(2x-3)(x-5x^2+3)`
`=2x^2-10x^3+6x-3x+15x^2-9`
`=-10x^3+17x^2+3x-9`
`g)5(x+4)-7(x+5)`
`=5x+20-7x-35`
`=-2x-15`
`h)6(x-3)+2(x-4)`
`=6x-18+2x-8`
`=8x-26`
`k)3x^2+6(x-3)+7x(5x)`
`=3x^2+6x-18+35x^2`
`=37x^2+6x-18`
`l)(3x-2)(5-6x)+3x(x-4)`
`=15x-18x^2-10+12x+3x^2-12x`
`=-15x^2+15x-10`