Kunci Jawaban Matematika Kelas 9 Halaman 81 Ayo Kita Tinjau Ulang, Persamaan Kuadrat

(a + b)² = a² + 2ab + b²

x² + 7x = -3

x² + 7x + (7/2)² = -3 + (7/2)²

(x + 7/2)² = -3 + 49/4

(x + 7/2)² = - 12/4 + 49/4

(x + 7/2)² = 37/4

x + 7/2 = ±√37/4

x + 7/2 = ±√37/√4

x + 7/2 = ±√37/2

x₁ = √37/2 – 7/2