Somebody please help me.

What is f(3) for the quadratic function f(x)= 2x^2+ + x - 12

Write and solve a real word problem that involves determining distance on a coordinate plane

The point of intersection of the diagonals of a rectangle is 4 cm further away from the smaller side then from the larger side of the rectangle. the perimeter of the rectangle is equal to 56 cm. find the lengths of the sides of the rectangle. 16 points answer quick