We have 2x2 -6x -7 =0
a = 2, b = -6, c = -7
Please Follow this rule:
When the discriminant (b2 - 4ac) is greater than 0, there are two distinct real roots.
When the discriminant is equal to 0, there is exactly one real root.
When the discriminant is less than zero, there are no real roots, but there are exactly two distinct imaginary roots.
hope that helps