g) x^3 – 10x ² + 15x = 0 ( 5x- 3x ) ² – ( 1- 2x) ² = 0 x ³ – x ² + x- 1= 0

Giải thích các bước giải:

`x^3 – 10x ^2 + 15x = 0`

`=>x(x^2 – 10x + 15) = 0`

`=>x(x-5-sqrt10)(x-5+sqrt10) = 0`

`=>`\(\left[ \begin{array}{l}x=0\\x=\sqrt{10}+5\\x=-\sqrt{10}+5\end{array} \right.\)

`( 5x- 3x )^2 – ( 1- 2x)^2 = 0`

`=>(2x)^2-(1-2x)^2=0`

`=>(2x-1+2x)(2x+1-2x)=0`

`=>4x-1=0`

`=>x=1/4`

`x^3 – x^2 + x- 1= 0`

`=>x^2(x-1)+(x-1)=0`

`=>(x^2+1)(x-1)=0`

Mà `x^2+1>0AAx`

`=>x-1=0`

`=>x=1`