Giải phương trình: -8/(x-3) + 20/(x+1) = -4 26/11/2021 Bởi Alexandra Giải phương trình: -8/(x-3) + 20/(x+1) = -4
`-8/(x-3) + 20/(x+1) = -4` `⇔20(x−3)-8(x+1)=-4(x+1)(x-3)` `⇔12x-68+4x^2-8x-12=0` `⇔4(x−20+x^2)=0` `⇔(x-4)(x+5)=0` ⇔\(\left[ \begin{array}{l}x-4=0\\x+5=0\end{array} \right.\) ⇔\(\left[ \begin{array}{l}x=4\\x=-5\end{array} \right.\) Bình luận
ta có:-8(x-3)+20(x+1)=-4 <=>-8x+24+20x+20=-4 <=>12x+48<=>-4 <=>12x=-4-48 <=>12x=-48 <=>x=-4 Bình luận
`-8/(x-3) + 20/(x+1) = -4`
`⇔20(x−3)-8(x+1)=-4(x+1)(x-3)`
`⇔12x-68+4x^2-8x-12=0`
`⇔4(x−20+x^2)=0`
`⇔(x-4)(x+5)=0`
⇔\(\left[ \begin{array}{l}x-4=0\\x+5=0\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=4\\x=-5\end{array} \right.\)
ta có:-8(x-3)+20(x+1)=-4
<=>-8x+24+20x+20=-4
<=>12x+48<=>-4
<=>12x=-4-48
<=>12x=-48
<=>x=-4