Question

Ada yg tau no 3?
mohon bantuannya...

Answer 1

A. (x² - 9x) / (x² - 4x - 45)
= x (x - 9) / (x - 9)(x + 5)
= x/(x + 5)

b. 3/(a + 2) - (a - 5)/(a² - 4)
= 3/(a + 2) - (a - 5)/(a + 2)(a - 2) **samakan penyebut menjadi (a + 2)(a - 2)
= 3(a - 2)/(a + 2)(a - 2) - (a - 5)/(a + 2)(a - 2)
= (3a - 6)/(a + 2)(a - 2) - (a - 5)/(a + 2)(a - 2)
= (3a - 6 - a + 5)/(a + 2)(a - 2)
= (2a - 1)/(a + 2)(a - 2)

c. a² / (a² + a - 12) : (a² + 3a) / (2a - 6)
= a² / (a - 3)(a + 4) : a (a + 3) / 2(a - 3) **ingat kalau pembagian dibalik penyebut dan pembilangnya*
= a² / (a - 3)(a + 4) x 2(a - 3) / a (a + 3) ** coret (a - 3) dan a
= a / (a + 4) . 2(a - 3) / (a + 3)
= 2a (a - 3) / (a + 4)(a + 3)

d. (x² + x - 56) / (7 - x)
= (x + 8)(x - 7) / -(x - 7)
= -(x + 8)
= 8 - x