Respuesta :

Explanation:

(f o g)(x)

= f[g(x)]

= f(3x + 7)

= 5(3x + 7) - 4

= 15x + 31.

When (f o g)(k) = 7, 15k + 31 = 7.

=> 15k = -24, k = -8/5 = -1.6.