Using the discriminant to determine the number of roots

1

Determine the nature of the roots of y=x^2+8x+5

2

Determine the nature of the roots of y=x^2-4x+5

3

Determine the nature of the roots of y=3-7x+{2x}^2

4

Determine the nature of the roots of y={x}^2+7x-2

5

Given that kx^{2}+5x-\frac{5}{4}=0 has equal roots, what is the value of k?