Toán `x/3`=`y/4`=`z/5` ,2x^2+2y^2-3z^2=-100 timf x,y,z 16/07/2021 By Kinsley `x/3`=`y/4`=`z/5` ,2x^2+2y^2-3z^2=-100 timf x,y,z
Đặt `x/3=y/4=z/5=k` `⇒x=3k; y=4k;z=5k` Ta có : `2x^2+2y^2−3z^2=−100` `⇒18k^2+32k^2−75k^2=−100` `⇒−25k^2=−100` `⇒k^2=4` `⇒k=±2` xét `k=2⇒x=6; y=8; z=10` xét `k=−2⇒x=−6; y=−8; z=−10` Trả lời
Munz k
Đặt `x/3=y/4=z/5=k`
`⇒x=3k; y=4k;z=5k`
Ta có :
`2x^2+2y^2−3z^2=−100`
`⇒18k^2+32k^2−75k^2=−100`
`⇒−25k^2=−100`
`⇒k^2=4`
`⇒k=±2`
xét `k=2⇒x=6; y=8; z=10`
xét `k=−2⇒x=−6; y=−8; z=−10`