已知log5(x+2x-2)=0,2log5(x+2)-log5y+1/2=0,求y的值

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已知log5(x+2x-2)=0,2log5(x+2)-log5y+1/2=0,求y的值
已知log5(x+2x-2)=0,2log5(x+2)-log5y+1/2=0,求y的值

已知log5(x+2x-2)=0,2log5(x+2)-log5y+1/2=0,求y的值
log5(x+2x-2)=0 x+2x-2=1 x+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(3)+log5(5^1/2)=log5(9√5) y=9√5

log5(x^2+2x-2)=0,即 x^2+2x-2=1 x=1或x=-3(舍去) 2log5(x+2)-log5y+1/2=0,即 log5[3^2√5/y]=0,即 9√5/y=1 y=9√5 求采纳