Answer: 53
Explanation:
There is no diagram here but I am assuming QR and ST are parallel, otherwise I believe the question isn't possible.
Two pairs of sides are parallel in a parallelogram, meaning they are equal.
As a result, we can make the two equation for the lengths equal to each other.
5x-12 = 2x+27
3x = 27+12
3x = 39
x = 13
Now that have found x, we can substitute this back into the equation for the length of ST.
2x+27
2(13) + 27
= 53