Tentukan akar persamaan kuadrat berikut dengan menggunakan rumus abc.

1. x² – 2x – 15 = 0
a = 1, b = -2, c = -15

X1,2 = -b ± √b² – 4ac / 2a
X1,2 = -(-2) ± √(-2)² – 4.1.(-15) / 2.1
X1,2 = 2 ± √4 + 60 / 2
X1,2 = 2 + √64 / 2
X1,2 = 2 ± 8 / 2

X1 = 2+8/2 = 10/2 = 5
X2 = 2 – 8/2 = -6/2 = -3

HP = { -3 dan 5 }

2. 6x² – 7x – 3 = 0
a = 6, b = -7, c = -3

X1,2 = -b ± √b² – 4ac / 2a
X1,2 = -(-7) ± √(-7)² – 4.6.(-3) / 2.6
X1,2 = 7 ± √49 + 72 / 12
X1,2 = 7 ± √121 / 12
X1,2 = 7 ± 11 / 12

X1 = 7+11/12 = 18/12 = 3/2

X2 = 7 – 11/12 = -4/12 = -1/3

HP = { -1/3 dan 3/2 }

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Mapel : Matematika
Kelas : 8
Materi : Persamaan Kuadrat
Kata kunci : Rumus ABC
Kode Kategorisasi : 8.2.6