How many are functions? 1.(5,2)(9,0)(2,5)(5,7)
2.(-2,5)(-4,7)(-9,10)(-11,12)
3.(3,-5)(7,9)(2,3)(-5,9)
4.(4,7)(-2,5)(-2,6)(-5,10)
10 POINTS PLS HELP!

Find and simplify an expression for the area of five rows of x squares with side lengths of x centimeters .

Determine whether the quadrilateral below is a parallelogram. justify/explain your answer (this means back it up! give specific information that supports your decision. writing just "yes" or "no" will result in no credit.)

Angle that produces maximum distance