`Giai phương trình ` $\dfrac{60}{x - 10}$`- 60/x = 3/10 `
2 câu trả lời
Giải thích các bước giải:
`(60)/(x-10)-(60)/x=3/(10)`
ĐKXĐ: `x \ne 10; x \ne 0`
`=>60.10.x-60.10.(x-10)=3.x.(x-10)`
`<=>600x-600(x-10)=3x^2 +30x`
`<=>600x-600x+6000-3x^2 -30x=0`
`<=>6000-3x^2 +30x=0`
`<=>3(2000x-x^2 +10x)=0`
`<=>3(-x^2 +50x-40x+2000)=0`
`<=>3[-x(x-50)-40(x-50)]=0`
`<=>-3(x-50)(x+40)=0`
`<=>(x-50)(x+40)=0`
`<=>`\(\left[ \begin{array}{l}x-50=0\\x+40=0\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=50(tmđk)\\x=-40(tmđk)\end{array} \right.\)
`\text{Vậy phương trình có tập nghiệm: S}={-40;50}`
`60/(x-10)-60/x=3/10(xne10)`
`<=>(60x-60(x-10))/(x(x-10))=3/10`
`<=>(60x-60x+600)/(x^2-10x)=3/10`
`=>3(x^2-10x)=6000`
`<=>3x^2-30x-6000=0`
`<=>x^2-10x-2000=0`
`<=>x^2-50x+40x-2000=0`
`<=>(x^2-50x)+(40x-2000)=0`
`<=>x(x-50)+40(x-50)=0`
`<=>(x-50)(x+40)=0`
$⇔\left[\begin{matrix} x-50=0\\ x+40=0\end{matrix}\right.$
$⇔\left[\begin{matrix} x=50,tm\\ x=-40,tm\end{matrix}\right.$
Vậy `S={50;-40}`