Akar akar persamaan x²+(a-1)x+2 =0 adalah alfa dan beta. Jika a=2beta dan a>0, maka nilai a=

X² + (a-1)x +2 =0
α= 2β
α + β = -b/a = (a-1)
αβ = c/a = 2

αβ = 2
2β β= 2
β² = 1
β = ± 1

β = 1 > α= 2
β = -1 > α = -2 (tidak memenuhi karna α<0)

α +β= (a-1)
2 + 1 = ( a -1)
3 = a -1
a = 4