Question

Bantu jelasin no 10 & 11

Answer 1

10. -2x² + 13x = 15
-2x² + 13x - 15 = 0 
a = -2
b = 13
c = -15

x1 + x2 = -b/a
x1 + x2 = -13/(-2)
x1 + x2 = 13/2

x1 . x2 = c/a
x1 . x2 = -15/(-2)
x1 . x2 = 15/2

x1² + x2²
= (x1 + x2)² - 2x1 . x2
= (13/2)² - 2 . 15/2
= 169/4 - 15
= 169/4 - 60/4
= 109/4 = 27 1/4

Jawaban: B

11. x² + 3x - 4 = 0
a = 1
b = 3
c = -4

α + β = -b/a
α + β = -3/1
α + β = -3

α . β = c/a
α . β = -4/1
α . β = -4

Persamaan baru:
x² - (3α + 3β)x + 3α . 3β = 0
x² - 3(α + β)x + 9 . αβ = 0
x² - 3(-3)x + 9 . (-4) = 0
x² + 9x - 36 = 0

Jawaban: D

Answer 2

Jawaban dan penyelesaian ada di lampiran