The value of the discriminant of the quadratic equation $x^{2}-8x+15=0$ is ...... .

Solve the following quadratic equation using the quadratic formula,if the equation has a solution in $R$: $48m^{2} - 13m - 1 = 0$.

Which of the following equations has no real roots?

If the following quadratic equation has two equal and real roots,then find the value of $k$: $x^{2}-(k+10)x+9(k+1)=0$.

Answer the following and justify:
Can the quadratic polynomial $x^{2}+kx+k$ have equal zeroes for some odd integer $k > 1$?

Find the discriminant of the following quadratic equation and hence determine the nature of the roots of the equation: $x^{2}+5x+5=0$