If y varies directly as x and y is 400 when x is r when x is 4 what is the numeric constant of variation in this relation

Select the correct answer and solve for y

Which statement explains how you could use coordinate geometry to prove the opposite sides of a quadrilateral are congruent? a. use the slope formula to prove the slopes of the opposite sides are the same. b. use the slope formula to prove the slopes of the opposite sides are opposite reciprocals. c. use the distance formula to prove the lengths of the opposite sides are the same. d. use the distance formula to prove the midpoints of the opposite sides are the same.

7+(3n++8) what is the answer to this?