Let's find the value of each variable one at a time.
Value of y
Notice that the angles measuring 3y-20 and 4y+4 are consecutive angles. There is a theorem which says that if a quadrilateral is a parallelogram, then its consecutive angles are supplementary. Therefore, the measures of our consecutive angles add up to 180.
3y-20+ 4y+4=180
Let's solve it!
Notice that the angles that measure 4y+4 and 4x are opposite angles. Recall the theorem, which tells us that if a quadrilateral is a parallelogram then its opposite angles are congruent. Therefore, the measures of these angles are equal.
4y+4= 4x
We already know that the value of y is 28, so let's substitute it into our equation.
4(28)+4=4x
Let's solve this equation to find x.
