Okay story is my teacher assigned us work in class after we learned how to solve exponential equations (with variables as exponents and multiplication signs between bases). This was way too easy for me and so Idid it but I saw other questions with subtration and addition so I was curious and tried it. But I can't figure out how to even start it off. This is for my own entertainment not for marks.

Example of a question,

4^x + 4^(x+1) = 40

So what I tried was expanding 4^(x+ 1) into 4(4^x) and I for some reason still couldn't get it. I used my guess-ta-mation skills and got x= 1.5 but I lack the steps to get there. I would also like to avoid log.

Thanks for trying if you do.