Fungsi f dan g didefinisikan dengan rumus f(x) = 5x-8 dan g(x) = 3x + 4. Jika nilai f(n) =g(n), tentukan

A. f (n) = 5n-8
g (n) = 3n+4

b. f (n) = g (n)
5n-8 = 3n+4
5n-3n = 4+8
2n = 12
n = 6

c. f (3n) = 5 (3n)-8 = 15n-8
n = 6 –> f (3n) = 15.6-8 = 90-8 = 82

g (4n) = 3 (4n)+4 = 12n+4
n=6 –> g (4n) = 12.6+4 = 72+4 = 76

B. Nilai n
f(n)=g(n)
5n-8=3n+4
5n-3n=4+8
2n=12
n=12/2
n=6
a. Nilai f(n) dan g (n)
Nilai f(n)=5n-8
f(6)=5(6)-8
=30-8
=22
Nilai g(n)=3n+4
=3(6)+4
=18+4=22
c. f(3n) + g (4n)
f(3n)=5(3n)-8
=5(3×6)-8
=5(18)-8
=90-8
=82
g (4n)= 3(4n)+4
=3(4×6)+4
=3(24)+4
=72+4
=76
Jadi, f(3n) +g(4n)=82+76=158