Ответы и объяснения

2013-01-17T13:10:11+04:00

1.  12x^2+13x+1=0

Д = в^2 - 4ac = 169 - 4 * 12 * 1 = 169 - 48 = 121 = 11^2

x1 = -b + sqrt(Д)/ 2a = -13 + 11 / 24 = 2 / 24 = 1 / 2

x2 = -b - sqrt(Д)/ 2a = -13 - 11 / 24 = -24 / 24 = -1

 

2. 5x^2 - 13x +1 = 0

Д = в^2 - 4ac = 169 - 4 * 5 * 1 = 169 - 20 = 149

x1 = -b + sqrt(Д)/ 2a = 13 + sqrt(149) / 10

x2 = -b - sqrt(Д)/ 2a = 13 - sqrt(149) / 10

 

3. x^2 + 7x - 8=0

Д = в^2 - 4ac = 49 + 32 = 81 = 9^2

x1 = -b + sqrt(Д)/ 2a = -7 + 9 / 2 = 2 / 2 = 1

x2 = -b - sqrt(Д)/ 2a = -7 - 9 / 2 = -16 / 2 = -8

 

sqrt - корень