The measures of the angles of △RST are given by the expressions in the table. Angle Measure
R 31°
S ​(x+4)∘
T ​(3x+9)∘
Find the value of x. Then find the m∠S and m∠T.



Enter your answers in the boxes.
x =

​ m∠S= ​
º

​ m∠T= ​
º