若(x+2y+2)2与根号2x+y-5互为相反数,求x+y的平方根
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若(x+2y+2)2与根号2x+y-5互为相反数,求x+y的平方根
若(x+2y+2)2与根号2x+y-5互为相反数,求x+y的平方根
若(x+2y+2)2与根号2x+y-5互为相反数,求x+y的平方根
(x+2y+2)²+√(2x+y-5)=0 且有:(x+2y+2)²≥0,√(2x+y-5)≥0
所以有:
(x+2y+2)²=0 即:x+2y+2=0 .1
√(2x+y-5)=0即:2x+y-5=0.2
1、2两式相加得:
3x+3y-3=0 得:x+y=1
可得x+y的平方根为±1