Question

x^2+6x-7=0
Решите уравнение

Answer 1

х^2+6х-7=0

D=b^2-4ac=36+28=64

корень из D=8

х1= -7

х2= 1

Answer 2

${x}^{2} + 6x - 7 = 0 \\ d = {b}^{2} - 4ac = {6}^{2} - 4 \times 1 \times ( - 7) = 36 + 28 =64 = {8}^{2} \\ x1 = \frac{ - b + - \sqrt{d} }{2 \times a} = \frac{ - 6 + 8}{2 \times 1} = \frac{2}{2} = 1 \\ x2 = \frac{ - 6 - 8}{2 \times a} = \frac{ - 14}{2 \times 1} = - 7$