tolong sama jalannya ya..

f(x) = 2x + 5
g(x) = x - 1 / x + 4

(f o g)(a) = 5
2( x - 1 / x + 4 ) + 5 = 5
2x - 2 / x + 4 + 5 = 5
2x - 2 + 5x + 20 / x + 4 = 5
7x + 18 / x + 4 = 5

7a + 18 / a + 4 = 5
7a + 18 = 5a + 20
2a = 2
a = 1

Jawabannya D