# If f(x)= 2x+1, what is #f(x+2)?

May 25, 2015

Simle. You substitute $x$ for $x + 2$:

$f \left(x + 2\right) = 2 \left(x + 2\right) + 1$
$f \left(x + 2\right) = 2 x + 4 + 1$
$f \left(x + 2\right) = 2 x + 5$

You do the same as you'd do if it was asking the value for your function when $x$ equals some number. For example, what's $f \left(3\right)$ in this case?

$f \left(3\right) = 2 \left(3\right) + 1 = 7$

And f(0)?

$f \left(0\right) = 2 \left(0\right) + 1 = 1$

:)