Theory question 102
Indices and LogarithmsSolve the simultaneous equations log2x − log2y = 2, log2(x − 2y) = 3
Show the model answer
Model answer
log2(x/y) = 2, so x = 4y
x − 2y = 23 = 8
4y − 2y = 8, y = 4
x = 16
Explanation
Combine the logs into a single log, then remove the logs to get two ordinary equations.