suppose that 3^a=2 and 3^v=5. If 3^x=150, then write an expression for x in terms of a and b.
3a = 2 3b = 5 ---> 3a · 3b = 2 · 5 ---> 3a + b = 10
3x = 150 = 15 · 10 ---> 3x = 15 · 3a + b
Since 15 = 3log(15) / log(3) ---> 3x = 3log(15) / log(3) · 3a + b
---> x = [ log(15) / log(3) ] + a + b