Jawabanmu

2014-05-13T22:24:36+07:00
No.3
bilangan itu adalah 10,12,14
No.1
x2+ (k+2) x + (k+3)=0
misal akar kembar itu = a
maka
a + a = (k+2)
2a = (k+2)
a = (k+2)/2

a x a = (k+3)
a^2 = (k+3)
substitusi a = (k+2)/2
sehingga
a^2 = (k+3)
[(k+2)/2]^2 = (k+3)
[(k+2) ^2] /4 = (k+3)
[(k+2) ^2] = 4(k+3)
k^2 + 2k + 4 = 4k + 12
k^2 + 2k - 4k + 4 - 12 = 0
k^2 – 2k - 8 = 0
(k - 4)(k + 2) = 0
Jadi nilai k = 4 atau k = -2