Tolong dijawab ya...

[tex]gof(x) = g(f(x)) \\gof(x) = g(3x + 1) \\ gof(x) = \frac{(3x + 1) - 3}{(3x + 1) + 1} \\ gof(x) = \frac{3x -2 }{3x + 2} [/tex]
gof(a) = - 1/3 maka
[tex]gof(x) = \frac{3x - 2}{3x + 2} \\ gof(a) = \frac{3a - 2}{3a + 2} \\ - \frac{1}{ 3} = \frac{3a - 2}{3a + 2} \\ 3(3a - 2) = - 1(3a + 2) \\ 9a - 6 = - 3a - 2 \\ 9a + 3a = - 2 + 6 \\ 12a = 4 \\ a = \frac{4}{12} \\ a = \frac{1}{3} [/tex]
Semoga dapat dipahami