geometry
posted by matt .
determine the values of x and y for which ABCD is a parallelogram. AB = 3x + 7, BC = y +8, CD = 5x + 1, DA = 2y  3

The opposite sides are equal:
AB = CD
3x + 7 = 5x + 1
3x  5x = 1  7
2x = 6
X = 3.
BC = DA
y + 8 = 2y  3
y  2y = 3 8
y = 11
Y = 11.