Đáp án:
Giải thích các bước giải:
`1,3x - 15 = 2x (x-5)`
`<=>3(x-5)-2x (x-5)=0`
`<=>(3-2x)(x-5)=0`
⇔\(\left[ \begin{array}{l}x=\dfrac{3}{2}\\x=5\end{array} \right.\)
`2,x^2 - x= 0`
`<=>x(x-1)=0`
⇔\(\left[ \begin{array}{l}x=0\\x=1\end{array} \right.\)
`3,x^2 - 3x = 0`
`<=>x(x-3)=0`
⇔\(\left[ \begin{array}{l}x=0\\x=3\end{array} \right.\)
`4, x^2 - 2x = 0`
`<=>x(x-2)=0`
⇔ \(\left[ \begin{array}{l}x=2\\x=0\end{array} \right.\)
`5,(x + 1) ( x+ 4) = ( 2 - x) (x + 2)`
`<=>(x + 1) ( x+ 4) +( x-2) (x + 2)=0`
`<=>x^2+5x+4+x^2-4=0`
`<=>2x^2+5x=0`
`<=>x(2x+5)=0`
⇔\(\left[ \begin{array}{l}x=0\\x=-\dfrac{5}{2}\end{array} \right.\)
