Answer:
D. -9
Step-by-step explanation:

Hi there!
We know that RST is an equilateral(all 3 sides the same length) triangle, and is therefore equiangular(all 3 angles the same value). Therefore, angle S and is equal to one-third of the triangle's angle measure.
180/3=60
60=7x+4
56=7x
x=8
-AwesomeRepublic :)
For the more amount of the time the larger it will grow.