Solve the equation 3^(5x-2)=4^(6-x), and show that the solution can be written in the form log10(a)/log10(b).

So we have the equation initially in the form 3^(5x-2)=4^(6-x), and as the solution involves log10, then  a sensible first move would be to take log10 of both sides, giving log10(3^(5x-2)) = log10(4^(6-x)).

Using the log law that loga(k) = kloga, we can rewrite this as (5x-2)log10(3) = (6-x)log10(4).

Then expanding the brackets, and taking the x values to one side and the constants to the other gives, 5xlog10(3) + xlog10(4) = 6log10(4) + 2log10(3).

Taking x out as a factor, we get x(5log10(3) + log10(4)) =  6log10(4) + 2log10(3).

Using the log law we made use of earlier in the question (loga(k) = kloga), this can be written as x(log10(243) + log10(4)) = log10(4096) + log10(9).

We can then use the log law, loga(b) + loga(c) = loga(bc), to write the equations as x(log10(972)) = log10(36864). 

Now all we have to do is divide by log10(972), and we have our answer, so,

x = log10(36864) / log10(972).

EB
Answered by Eloise B. Maths tutor

6170 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Sketch the graph y=Ax^2 where A is a constant


How would the integral ∫x^2sin2xdx be solved using integration by parts?


How would I use implicit differentiation to differentiate functions such as: y=tan^-1(ax^2+b) in the form of dy/dx=.....?


A ball is thrown in the air. The height of the ball at time t is given by: h=5+4t-2t^2. What is its maximum height? At what time does the ball reach this height?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2026 by IXL Learning