Let's find the value of each variable one at a time.
Value of x
Notice that the side of length 2x+3 and the side of length x+7 are opposite. Recall the Parallelogram Opposite Angles Theorem says that if a quadrilateral is a parallelogram, then its opposite sides are congruent. Therefore 2x+3= x+7.
Let's solve it!
Notice that the side of length y+11 and the side of length 3y-5 are opposite. Recall the Parallelogram Opposite Angles Theorem says that if a quadrilateral is a parallelogram, then its opposite sides are congruent. Therefore y+11= 3y-5. Let's solve this equation, too.