$\displaystyle 3^{x+1} + 3^{x+2}$
How do I simplify this?
okay ...
$\displaystyle 3^2 = 3^1 \cdot 3^1 $
so
$\displaystyle 3^{x+1} = 3^x \cdot 3^1 $
now you can write
$\displaystyle 3 \cdot 3^x + 3^2 \cdot 3^x $
here you see both of them have common $\displaystyle 3^x$ so you can pull it out ...
$\displaystyle yx +2x = x (y+2 ) $
same thing
$\displaystyle 3 \cdot 3^x + 3^2 \cdot 3^x = 3^x ( 3 + 3^2 ) $