Respuesta :

Answer:   k(9)=63  

              f(x)=15= 37

Step-by-step explanation:

k(x)=x^2-18

k(9)=(9)^2-18

      =81-18

k(9)  =63

f(x)=2(x)+7

when f(x)=15

  f(15)=2(15)+7

         =30+7

 f(15)  = 37

Step-by-step explanation:

k(x) = 2x - 18

k(9) = (2 x9) -18

k(9) = 18-18

k(9) = 0

b

B...f(x) = 15

2x + 7 = 15

2x = 15 - 7

2x = 8

x= 8

2

x= 4