Jawabanmu

2014-01-10T21:50:15+07:00
Beda =  U_{n} -U_{n-1} -3
        =  U_{2} - U_{1}  
        = -6 - (-9)
        = 3
2014-01-10T22:17:40+07:00
A = -9
masukkan ke salah satu rumus U₂ atau U₃
U₂ = -9 +b = -6
b = 3