Question

Can someone help solve this one ? I can’t solve it and it would be very helpful if you can explain thanks you.

Answer 1

Hello,

Let's say y= log(x) in base 10.

$\\y=log(x)\\\\log^2(x)-3log(x)-4=0\\\\y^2-3y-4=0\\\\\Delta=9+16=5^2\\\\y=4\ or\ y=-1\\\\log(x)=4 \Longrightarrow x=10^4\\\\or\\\\log(x)=-1 \Longrightarrow x=10^{-1}=0.1$