Please help me! I don't understand this its confusing to me :(

Determine which expressions represent real numbers and which expressions represent complex number. asaaap! plis!

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. x^2 + 4x + 5 = 0

The domain of a function can be represented by which one of the following options? o a. a set of output values o b. a set of f(x) values o c. a set of input values o d. a set of both input and output values