f (x)=2x-10,g (x)=3x+k dan (fog)(x)=(gof)(x) maka nilai kita?

f(x) = 2x - 10 dan.g(x) = 3x + k
fog (x) = f { g(x) }
= f (3x + k')
= 2(3x + k) -10
= 6x + 2k. -10
gof (x) = g (2x -10)
= 3(2x -10) +k
= 6x - 30 + k
fog (x: = gof (x)
6x + 2k -10 = 6x -30 + k
k = -20

[Fungsi Komposisi dan Fungsi Invers]

fog(x) = gof(x)
f(g(x)) = g(f(x))
2(3x + k) - 10 = 3(2x - 10) + k
6k + 2k - 10 = 6x - 30 + k
2k - 10 = k - 30
k = -20