已知log5(xˆ2;+2x-2)=0,2log5(x+2)-log5y+1/2=0,求y值
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已知log5(xˆ2;+2x-2)=0,2log5(x+2)-log5y+1/2=0,求y值
已知log5(xˆ2;+2x-2)=0,2log5(x+2)-log5y+1/2=0,求y值
已知log5(xˆ2;+2x-2)=0,2log5(x+2)-log5y+1/2=0,求y值
log5(x²+2x-2)=0
x²+2x-2=1
x²+2x-3=0
(x-1)(x+3)=0
后面的真数x+2>0
所以x=1
2log5(x+2)-log5y+1/2=0
2log5(3)-log5(y)+1/2=0
log5(y)=log5(3²)+log5(5^1/2)=log5(9√5)
y=9√5