Explain how to round a number when 7 is to the right of the rounding digit

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.)

F(x)=x/2-2 and g(x)=2x^2+x-3 find (f+g)(x)

Cd is the perpendicular bisector of both xy and st, and cy=20. find xy.