Question 96003
you are right about changing the base ... 2^2=4 so log(base2)4=2 ... so log(base2)9x^2=2(log(base2)(5x-8))


multiplying a log by 2 means squaring the argument ... 9x^2=(5x-8)^2 ... taking square root gives 3x=5x-8 and -3x=5x-8


so x=4 and x=1 ... but remember, logs are undefined for negative arguments [5(1)-8=-3] ... so 4 is the solution