[toán 12] bt log

T

tuonghuy333_2010

Giải đáp

${x}^{log_3^2x-5log_3x+7}=x$.Đk: x>0
Đặt $t=log_3x$ \Rightarrow $t(t^2-5t+7)=t$ \Rightarrow t=0 or t=3 or t=2 \Rightarrow x=1;x=3;$x=log_32$
 
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