Question

Решите три уравнения
Два не полных

Answer 1

1) X1 = 13, X2 = -15

2) X1 = 6, X2 = 1

3) X1 = 1, X2 = -2006

Объяснение:

1) x²+2x-195=0

a =1, b =2, c = -195

D = b²-4ac

D = 4-4·1·(-195) = 4+780 = 784

D>0, 2 корня

X1/2 = $\frac{-b+-\sqrt{D} }{2a}$ = $\frac{-2+-28}{2}$ = X1 = 13, X2 = -15

2) 3x²-7x+2=0

a = 3, b = -7, c = 2

D = b²-4ac

D = (-7)²-4·3·2 = 25

D>0, 2 корня

X1/2 = $\frac{-b+-\sqrt{D} }{2a}$ = $\frac{-(-7) +-5}{2}$ = X1 = 6, X2 = 1

3) x²+2005x-2006=0

a = 1, b = 2005, c = -2006

D = b²-4ac

D = 2005²-4·1·(-2006) = 4.028.049

D>0, 2 корня

X1/2 = $\frac{-b+-\sqrt{D} }{2a}$ = $\frac{-2005+-2007}{2}$ = X1 = 1, X2 = -2006