One third of a number increased by 7 is five. What is the number?

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

The diagonals of a quadrilaretral intersect at (-1,4). one of the sides of the quadrilateral is bounded by (2,7) and (-3,5) determine the coordinates of the other side in order for the quadrilaretral to be a square.

Can someone, me with this.i really need with this