Jawaban:

detail dipenjelasan

Penjelasan dengan langkah-langkah:

Untuk setiap persamaan kuadrat ax^2 + bx + c = 0 , dan akar - akarnya x1 dan x2 , maka :

jumlah akar => x1 + x2 = - b/a

selisih akar => x1 − x2 = ±√D/a = ±√(b^2 - 4.a.c)/a

perkalian akar => x1.x2 = c/a

1.x^2 + 6x +2=0

x1 + x2 = - b/a = -6/1 = - 6

x1 − x2 = ±√D/a = ±√(b^2 - 4.a.c)/a

= ±√(6^2 - 4.1.2)/1

= ±√(36 - 8)

= ±√(28)

= ±√(4 ×7)

= ± 2√7

x1.x2 = c/a = 2/1 = 2

2. 7x² - 12x +8=0

x1 + x2 = - b/a = 12/1 = 12

x1 − x2 = ±√D/a = ±√(b^2 - 4.a.c)/a

= ±√((-12)^2 - 4.7.8)/7

= ±√(144 - 224)/7

= ±√(- 80)7

x1.x2 = c/a = 8/7

3. 2x^2 + 3x-6=0

x1 + x2 = - b/a = - 3/1 = - 3

x1 − x2 = ±√D/a = ±√(b^2 - 4.a.c)/a

= ±√(3^2 - 4.2.(-6))/2

= ±√(9 + 48)/2

= ±√(57)/2

x1.x2 = c/a = -6/2 = -3