Question

Please bantu jawab please nomer 8

Answer 1

N(AUB) = 40
n(A n B) = x
n(A-B) = 2x^2 + 2
n(B-A) = 9x + 10
n(A- B) = n(A) - x --> n(A) = 2x^2 +x+ 2
n(B-A) = n(B) - x--> n(B) = 9x + 10 + x = 10 x + 10

n(AUB) = n(A) + n(B) - n(A n B)
40 = 2x^2 + x + 2 + 10 x + 10  - x
40 = 2x^2 + 10 x + 12
2x^2 + 10 x - 28 = 0
x^2 + 5x - 14 = 0
(x+7)(x-2) = 0
x = -7 (tm) atau x = 2
jika x = 2 -->  n(A - B) = 2x^2 + 2 = 10