Question

If log 16 = a, log 9 = b and log 5 = c, evaluate the following in terms of a, b, c: log 12

Answer 1

log16 = a, log9 = b and log5 = c
log4² = a, log 3² = b and log5 = c
2log4 = a, 2log3 = b and log5 = c
`"log"4 = "a"/(2), "log"3 = "b"/(2) and "log"5` = c
Consider, log12 = log(4 x 3)
= log4 + log3
= `"a"/(2) + "b"/(2)`

= `("a" + "b")/(2)`.