The variables x and y are related by y = 5^x. How do I find the value of x when y is set to 15?
15 = 5^x, we can easily solve this equation by using logs on either side which will give us: log15 = x log 5. Then by solving this for x, we get the result of 1.68 to two decimal places.
AB
Related Maths A Level answers
All answers ▸How to gain an inverse function
Find dy/dx when y = x(4x + 1)^1/2
A curve has equation y = (x-1)e^(-3x). The curve has a stationary point M. Show that the x-coordinate of M is 4/3.
Solving harder exponential equations, e.g. 5/[exp(x) + 6exp(-x)] - 1 = 0 . CORE MATHS.