SOSSOSSOSSOSSOS GIÚP MIK VS MÌNH RẤT CẦN

Đáp án+Giải thích các bước giải:

`a)`

`(3x-1)(2x+7)-(x+1)(6x-5)=16`

`=>6x^2+21x-2x-7-(6x^2-5x+6x-5)=16`

`=>6x^2+21x-2x-7-6x^2+5x-6x+5=16`

`=>(6x^2-6x^2)+(21x-2x+5x-6x)=16+7-5`

`=>18x=18`

`=>x=1`

Vậy `x=1`

`b)`

`(10x+9)x-(5x-1)(2x+3)=8`

`=>10x^2+9x-(10x^2+15x-2x-3)=8`

`=>10x^2+9x-10x^2-15x+2x+3=8`

`=>(10x^2-10x^2)+(9x-15x+2x)=8-3`

`=>-4x=5`

`=>x=-5/4`

Vậy `x=-5/4`

`c)`

`(3x-5)(7-5x)+(5x+2)(3x-2)-2=0`

`=>21x-15x^2-35+25x+15x^2-10x+6x-4-2=0`

`=>(-15x^2+15x^2)+(21x+25x-10x+6x)=35+4+2`

`=>42x=41`

`=>x=41/42`

Vậy `x=41/42`

`d)`

`x(x+1)(x+6)-x^3=5x`

`=>(x^2+x)(x+6)-x^3=5x`

`=>x^3+6x^2+x^2+6x-x^3-5x=0`

`=>(x^3-x^3)+(6x^2+x^2)+(6x-5x)=0`

`=>7x^2+x=0`

`=>x(7x+1)=0`

`=>[(x=0),(7x+1=0):}`

`=>[(x=0),(7x=-1):}`

`=>[(x=0),(x=-1/7):}`

Vậy `x\in{0;-1/7}`

`#ld`