Jika p+1 dab p-1 adalah akar akar persamaan x^2 - 4x + a=0, maka nilai a adalah....

x1 = p + 1 dan x2 = p - 1
x^2 - 4x + a = 0
x1 + x2 = -b/a
(p + 1) + (p - 1) = -(-4)/1
2p = 4
p = 2

x1.x2 = c/a
(p + 1)(p - 1) = a/1
(2 + 1)(2 - 1) = a
3(1) = a
a = 3