Persamaan kuadrat 〖2x〗^2+3x-a=0 memiliki akar-akar α dan β.jika α+2β=0 nilai a yang memenuhi adalah

α +2β = 0
α = -2β

2x² + 3x + a = 0

α + β = -b/a = -3/2
α * β = c/a = c/2

α + β = -b/a = -3/2
-2β + β = -β = -3/2
β = 3/2
α = -2β = -2(3/2) = -3

α * β = a/2
-2β * β = -2β² = -2 * (3/2)²
-2 * 9/4 = a/2
-9 = a