Ответ:
Объяснение:
Квадратные уравнения решаем по формуле дискриминанта.
D = b^2 - 4ac
x1 = -b + sqrt(D) / 2a
x2 = -b - sqrt(D) / 2a
1. х^2 + 7x + 6 = 0
D = 7^2 - 4*1*7 = 49 - 28 = 21
x1 = -7 + sqrt(21) / 2 = -3,5 + sqrt(21)/2
x2 = -7 - sqrt(21) / 2 = -3,5 - sqrt(21)/2
2. (x - 4) ^ 2 = 4x - 11
x^2 - 8x + 16 = 4x - 11
x^2 - 8x - 4x + 16 + 11 = 0
x^2 - 12x + 27 = 0
D = 12^2 - 4*1*27 = 144 - 108 = 36
x1 = 12 + 6 / 2 = 9
x2 = 12 - 6 / 2 = 3
3. -x^2 - 8x + 12 = 0
D = 64 - (- 48) = 100
x1 = 8 - 10 / -2 = 1
x2 = 8 + 10 / -2 = -9
4. -x^2 - 6x + 11 = 0
D = 36 + 44 = 80
x1 = 6 + sqrt(80) / -2 = -3 - sqrt(80)/2
x2 = 6 - sqrt(80) / -2 = -3 + sqrt(80)/2