3^2x-3^x-24=0
Could you also teach me the process in answering it?
Let 3^x = y
==> 3^2x - 3^x - 24 =0
= y^2 - y - 24 = 0
solve for y using quadratic equation.
You will get 2 answers for y, one positive, the other negative.
But 3^x = y,
thus equate 3^x = y for both answers of y.
Use log on both sides, and then solve for x.
You will see, when y is negative, you wont be able to use log, therefore, we neglect the negative.
Hope this helps.