Question

Решите уравнения:
Х^2-х-72=0

-4в^2+7в-3=0

Answer 1

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

Answer 2

D=b^2-4ac=(-1)^2-4*1*(-72)=1+288=$\sqrt{289}$=17
х1=$\frac{-b- \sqrt{D} }{2a} = \frac{1-17}{2} = \frac{-16}{2} =-8$
х2=$\frac{-b+ \sqrt{D} }{2a} = \frac{1+17}{2} = \frac{18}{2} = 9$
Ответ: -8 и 9

D=b^2-4ac=7^2-4*(-4)*(-3)=49-48=$\sqrt{1} =1$
х1=$\frac{-b- \sqrt{D} }{2a} = \frac{-7-1}{2*(-4)} = \frac{-8}{-8} =1$
х2=$\frac{-b+ \sqrt{D} }{2a} = \frac{-7+1}{(-8)} = \frac{-6}{-8} =0,75$