Tentukan rumus f-1 (x) dan f-1(3) untuk fungsi berikut A.f(x) = 1/2x + 2/3 B.f(x) =-2/3 (2x-1) C.f(x) = 4 (5-3x) Pake rumus ya :)

A) f(x) = ½x + ⅔
y = ½x + ⅔
½x = y - ⅔
x = 2(y - ⅔)
x = 2y - 4/3
f-¹(x) = 2x - 4/3
Atau
f-¹(x) = (6x - 4) / 3
f-¹(3) = (6(3) - 4) / 3 = 14/3

B) f(x) = -⅔ (2x - 1)
y = -4/3x + ⅔
4/3x = ⅔ - y
x= 3/4 (⅔ - y)
x = ½ - 3/4y
f-¹(x) = ½ - ¾x
Atau
f-¹(x) = (2 - 3x) / 4
f-¹(3) = (2 - 3(3)) / 4 = -7/4

C) f(x) = 4 (3 - 5x)
y = 12 - 20x
20x = 12 - y
x = (12 - y) / 20
f-¹(x) = (12 - x) / 20
f-¹(3) = (12 - 3) / 20 = 9/20