bang tolong jawapin

f(x) = 2x + p
g(x) = 3x + 120
diketahui f(g(x)) = g(f(x))

maka
2(3x + 120) + p = 3(2x + p) + 120
6x + 240 + p = 6x + 3p + 120
240 + p = 3p + 120
4p = 120
p = 30

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g(x) = x² - 1
fog(x) = x⁴

maka
f(g(x)) = x⁴
f(x² - 1) = x⁴
misal
y = x² - 1
x² = y + 1
x = √(y + 1)

f(y) = [√(y + 1)]⁴
f(y) = (y + 1)²
f(y) = y² + 2y + 1

f(4) = 4² + 2(4) + 1
f(4) = 16 + 8 + 1
f(4) = 25