Question

If ln x + ln(x-7)= ln7x, then x= ??
show working out

Answer 1

start with
\[\ln(x(x-7))=\ln(7x)\] then go right to
\[x(x-7)=7x\] and solve the quadratic

Answer 2

I get x^2-7x=14x?

Answer 3

x=0
x=21