Perform the indicated operation.

Question

g(n) = 4n-4

f(n) = 2n+1 

find (3g+5f) (-3y) 

Answer 1

I am assuming that this is function composition. In that case, the expression 

 

(3g+5f)of(-3y)

 

means to substitute n=-3y into the function (3g+5f)of(n). So we have,

 

(3g+5f)(-3y)

 

 

= (3[4n-4]+5[2n+1])of(-3y)

 

= 3[4(-3y)-4]+5[2(-3y)+1]

 

simplify and get

 

= -66y-7