Question

mohon bantuanya kaka2 yang dah bisa

Answer 1

4. (fog)⁻¹ (6) = ...
g⁻¹ o f⁻¹ (6) = g⁻¹ { f⁻¹(6)}
= g⁻¹{ (6-1)/(5) }
= g⁻¹ (5/5)
= g⁻¹(1) = (3-1)/(2) = 2/2 = 1

(fog)⁻¹(6) = 1

5.
a. misalkan (fogoh)⁻¹(x) = y
maka (fogoh) (y) = x
fog{ h(y)} = f o g {(y+1)/(y)}
= f { 2(y+1)/y   +5}
= 2(y+1)/y  + 5 - 4
= (2y+2)/y  + 1

(fogoh)⁻¹(x) = (2x +2)/x  + 1 atau = (2x+2 + x)/(x) 
(fogoh)⁻¹(x) = (3x+2)/(x)

b. h⁻¹ o g⁻¹ o f⁻¹ (a) = 2
(fogoh)⁻¹ (a) = 2
(3a + 2)/ a = 2
3a + 2 = 2a
a = - 2