Jawabanmu

2014-05-31T18:49:08+07:00
Ax^2 + 5x - 12 = 0
a(2)^2 + 5(2) - 12 = 0
4a +10 - 12 = 0
4a = -2
a = 1/2

Jawaban paling cerdas!
2014-05-31T19:03:50+07:00
Ax²+5x-12 = 0 , akarnya udah diketahui x =2
a.2²+5.2-12 = 0
4a+10-12 = 0
4a= 2
a= 1/2, masukin a ke ax²+5x-12 = 0
1/2x²+5x-12 = 0 , biar mudah dikali 2 jadi
x² + 10x +24
(x+12) (x-2) 
jawabannya x = -12, karena (x-2) udah  diketahui
1 5 1