What is the variable number in the equation 6=4+2s

In the polynomial below, what number should replace the question mark to produce a difference of squares? x2 + ? x - 36

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. 4x^2 + 20x + 25 = 0

Collin did the work to see if 10 is a solution to the equation r/4=2.4