Find (f+g)(2) and (f-g)(3)
f(x)=3*8^x
g(x)=2*8^x+1
( f + g) (2) = f(2) + g(2) =
[ 3*8^(2) ] + [ 2*8^(2) + 1 ] = [ 3 * 64 ] + [ 128 + 1 ] = [ 192 + 128 + 1 ] = 321
(f - g) (3) = f(3) - g(3) =
[ 3*8^3 ] - [ 2*8^3 + 1 ] = 8^3 - 1 = 511
