Question

Dik : f(x) = x2-4x-3 dan g(x)=x-5
tentukan :
a). (f+g) (x)
b). (f-g)(x)
c). (fg)(x)

mohon bantuannya ya :-)

Answer 1

Ingat :
(f + g)(x) = f(x) + g(x)
(f  - g)(x) = f(x) - g(x)
(fg)(x) = f(x) . g(x)
Jawab :

bagian a
= f(x) + g(x)
= x² - 4x - 3 + x - 5
= x² - 3x - 8

bagian b
= f(x) - g(x)
= x² - 4x - 3 - x + 5
= x² - 5x + 2

bagian c
= f(x) . g(x)
= (x² - 4x - 3)(x - 5)
= x³ - 5x² - 4x² + 20x - 3x + 15
= x³ - 9x² + 17x + 15