如果有理数x,y满足等式2x+x2+9y2+2=-6y,求x-3y的值.
如果有理数x,y满足等式2x+x2+9y2+2=-6y,求x-3y的值.
数学人气:362 ℃时间:2019-11-18 09:29:10
优质解答
由2x+x
2+9y
2+2=-6y,得
x
2+2x+1+9y
2+6y+1=0,
即(x+1)
2+(3y+1)
2=0,
∴x+1=0,3y+1=0,
解得x=-1,y=-
∴x-3y=-1-3×(-
)=-1+1=0.
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