Question

Prove that :-
$x ^{2} + 6x + 15$
has no zero.

Answer 1

D=$b^{2}-4ac$
  = 6*6 - 4*1*15
  = 36 - 60
  = -24

Since D is a negative value, there exist no REAL roots

Answer 2

x²+6x+15
D = b²-4ac
= 6²-4×1×15
= 36-60
= -24<0
so,the roots of this equation are imaginary,and we say that it has no real roots.