tolong donk dijawab.Tapi pakai Caranya

correct me of i wrong

9) 2x²-20x+42 = 0
------------------------------ :2
= x²-10x+21 = 0
= (x-3)(x-7)
x-3 = 0
x1 = 3
x-7 = 0
x2 = 7
x1+x2 = 3+7 = 10 (A)

10) x²+p = 0
x = -6
x²+p = p
(-6)²+p = 0
p = -36 (b)

Semoga membantu :)