Even Function

Q. Let $f\left(x\right)=a^x(a>0)$ be written as $f\left(x\right)=f_1\left(x\right)+f_2\left(x\right)$, where $f_1\left(x\right)$ is an even function and $f_2\left(x\right)$ is an odd function. Then $f_1(x+y)+f_1(x-y)$ equals :

1. $2f_1\left(x\right)f_1\left(y\right)$
2. $2f_1(x+y)f_1(x-y)$
3. $2f_1\left(x\right)f_2\left(y\right)$
4. $2f_1(x+y)f_2(x-y)$

Q. Draw the graph for f(x)=10-|x|

Q. sketch the graph of |x|+|y|=4