Given that ​f(x)=5x+8​, find ​(f◦​f)(−3​).

Answer 1

f(-3) = 5(-3) + 8 = -15 + 8 = -7

f comp f at x=-3 = f(f(-3)) = f(-7) = 5(-7) + 8 = -35 + 8 = -27

the other way to do it is:

5(5x+8)+8 at x=-3

5( 5*-3+8) + 8 = 5 ( -15+8)+8 = 5*-7+8 = -25+8 = -27