Answer:
f(4)=6
Explanation:
replace a with 4
f(4)=2(4+2)-6
the multiply thingy(i forgot what it was called ok) (2*4 and 2*2)
f(4)=8+4-6
do the easy math(i will write it out anyways though)
f(4)= 12-6
f(4)=6
i havnt done this for a while but this is what i remeber
dont report me if i was wrong pls