Question

show that the polynomial x2-6x+12 has no real zeroes

Answer 1

Sol:
x2 - 2x +  5
when compared with the standard form of the quadratic equation, a = 1, b = - 2, c = 5

Value of the discriminant = b2 - 4 ac
                                     = (-2)2 - 4(1) (5)
                                     = 4 - 20
                                     = - 15
The value of the discriminant is negative i.e less than zero.
Hence, the quadratic equation x2 - 2x +  5 has no real zeroes.

Answer 2

See the image and ask if there is any problem.