mohon bantuannya kawan beserta caranya ya..

jawab

5. 
f(x) = x-3
g(x) = x² + 2x - 5

gof(x)=  g{ f(x) }
= g (x -3)
= ( x- 3)² + 2 ( x-3) - 5
= x² -6x + 9 + 2x - 6 - 5
= x² - 4x  - 2

6.
f(x) = (2x+ 7)/ (5x - 3)
y = (2x  + 7)/(5x - 3)
y(5x - 3) = 2x + 7
5 xy - 3y = 2x + 7
4xy - 2x = 3y + 7
x(4y -2) = 3y + 7
x = (3y + 7)/(4y - 2)

f⁻¹ (x) = (3x + 7)/(4x - 2)

7.
Persamaan kuadrat 
8x - 5 = 3x² atau  3x² - 8x + 5 = 0
α+β = -b/a = - (-8)/3 = 8/3
α. β = c/a = 5/3

nilai 5/(6α) + 5/(6β) =  5/6 ( 1/α + 1/β)
= 5/6  (α+β)/(α β)
= 5/6 (8/3) / (5/3)
= 5/6 ( 8/3) (3/5)
= 5/6 (8/5)
= 8/6
= 4/3

8)  PK  x² + 2x - 3 = 0

PK  baru yang akar ny p+3 atau q +3
x = p+ 3
p = x - 3

Pk baru  (x - 3)² + 2(x - 3) -3 = 0
x² - 6x + 9 + 2x - 6 - 3 =0
x² - 4x = 0