What would this be!?

What is the difference between regular convex and concave polygons

Which of the following pairs of functions are inverses of each other? o a. f(x)=x72+8 and 96-9 = 7/x+2) =8 o b. f(x)= 6(x - 2)+3 and g(x) - *#2-3 o c. $4) = 5(2)-3 and 90- 4*: 73 o d. f(x) = 6)-12 and 910 – +12

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.