Diketahui x1 dan x2 adalah akar akar dari persamaan kuadrat x²-5x+k+3=0 dan x1²+x2²=13.nilai k yg memenuhi adalah...

x²-5x+k+3=0
a = 1
b = -5
c = k + 3
x1 + x2 = -b/a = -(-5)/1 = 5
x1 . x2 = c/a = k+3/1= k+3

x1^2 + x2^2 = 13
(x1 + x2)^2 - 2x1.x2 = 13
(5)^2 - 2(k+3) = 13
25 - 2k + 6 = 13
31 - 2k = 13
-2k = - 18
k = 9