(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Please , can anybody help me to do these and to explan to me?

I tried tried, but i can't do anything.

1. 4^{x-1}+ 4^{x}+ 4^{x-1}=84

2. 15 * 2^{x+1}+ 15 * 2^{ x-1}=135

3. 8^{x}+ 18= 2* 27^{x}

4. 3^{x-8}*3^{x/2}+15=0

5. 5^{x}- 5^{3-x}=20

2. Relevant equations

At the 5^{th}i do like this:

5^{x }- 5^{3-x}=5*4 /5

5^{x-1}-5^{2-x}=4 and i can't do more, i have just learn for exponential equations and I don't know so good , and that is the reason that i want to help me.the problem is that i want to solve,thanks

3. The attempt at a solution

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# Homework Help: Exponential equations homework

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