Answer:
i think is 2 but i am not sure
Area=legnth times width
if legnth=x
and
area=400
400=x times width
wait
SQUARE painting
legnth=width
width=x
400=x times x
400=x^2
sqrt both sides
20=x
answer is 20 in
equation is
400=x times x
Looks like the given function is

Recall that for |<em>x</em>| < 1, we have

We want the series to be centered around
, so first we rearrange <em>f(x)</em> :

Then

which converges for |(<em>x</em> - 4)/5| < 1, or -1 < <em>x</em> < 9.