Question

find the value of k for which the equation is X square + 5 x + 16 is equal to zero has a root

Answer 1

there is no k in the equation so
sorry mate !!!

Answer 2

we have
x^2+5kx+16=0

here,a=1,b=5k,and c=16

D=b^2-4ac
=(5k)^2-4(1)(16)
=25k^2-64

the given equation will have no real root if,D<0

=25k^2 - 64 < 0
=(5k)^2 - (8)^2 < 0
=(5k+8) (5k-8) < 0
=-8/5k < 8/5