Math Help - solving for x, exponential

1. solving for x, exponential

5^x - 5^(3-x) = 20

2. I'll kick this off for you,

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

$5^x - \frac{5^3}{5^x} = 20$

Now mulitply both sides through by $5^x$ we get

$5^{2x} - 5^3 = 20\times 5^x$

Making $a = 5^x$ then

$a^2 - 5^3 = 20a$