Решите уравнения: Х^2-х-72=0 -4в^2+7в-3=0

1. D = 1+4*(1*72) x1 = (1-17)/2 = -8 x1 = (1+17)/2 = 9 2. D = 49 - 4*(4*3) = 1 B1 = (-7-1)/(-8) = 1 B2 = (-7+1)/(-8) = 0.75

D=b^2-4ac=(-1)^2-4*1*(-72)=1+288=[latex] \sqrt{289} [/latex]=17 х1=[latex] \frac{-b- \sqrt{D} }{2a} = \frac{1-17}{2} = \frac{-16}{2} =-8 [/latex] х2=[latex] \frac{-b+ \sqrt{D} }{2a} = \frac{1+17}{2} = \frac{18}{2} = 9[/latex] Ответ: -8 и 9 D=b^2-4ac=7^2-4*(-4)*(-3)=49-48=[latex] \sqrt{1} =1[/latex] х1=[latex] \frac{-b- \sqrt{D} }{2a} = \frac{-7-1}{2*(-4)} = \frac{-8}{-8} =1[/latex] х2=[latex] \frac{-b+ \sqrt{D} }{2a} = \frac{-7+1}{(-8)} = \frac{-6}{-8} =0,75[/latex]