Đáp án$+$Giải thích các bước giải:

`a)5x(1/5x-2)+3(6-1/3x^2)=12`

`x^2-10x+18-x^2=12`

`-10x=12-18`

`x=3/5`

Vậy `x=3/5`

`--------`

`b)3x(4/3x+1)-4x(x-2)=10`

`4x^2+3x-4x^2+8x=10`

`11x=10`

`x=10/11`

Vậy `x=10/11`

`---------`

`c)5(x^2-3x+1)+x(1-5x)=x-2`

`5x^2-15x+5+x-5x^2=x-2`

`5x^2-15x+x-5x^2-x=-2-5`

`-15x=-7`

`x=7/15`

Vậy `x=7/15`

`----------`

`d)12x^2-4x(3x-5)=10x-17`

`12x^2-12x^2+20x=10x-17`

`12x^2-12x^2+20x-10x=-17`

`10x=-17`

`x=-17/10`

Vậy `x=-17/10`

`-----------`

`e)4x(x-5)-7x(x-4)+3x^2=12`

`4x^2-10x-7x^2+18x+3x^2=12`

`8x=12`

`x=3/2`

Vậy `x=3/2`