Question

Mohon bantuannya.soal persamaan kuadrat

Answer 1

1. y = ax² + bx + c
masukan (0,3)
3 = 0 + 0 + c
c = 3
y = ax² + bx + 3
-1 = -b/2a
2a = b
(-1,4)
4 = a - b + 3
1 = a - b
1 = a - 2a
1 = -a
a = -1
b = 2a = -2
persamaannya y = -x² - 2x + 3 (A)

2.  2x²+2x - 12 = 0
x² + x - 6 = 0
(x + 3) (x - 2) = 0
x2 = -3 atau x1 = 2
2x1 - 3x2 = 4 + 9 = 13 (B)