The value of x that makes the angles supplementary angels is 20
What is supplementary angles
Supplementary angles are angles that when added, sums up to 180 degrees.
Therefore, angle U and angle V are supplementary angles their sum will be 180 degrees.
This is solved using the equation'
angle U + angle V = 180 degrees
3x + 2(3x) = 180
3x + 6x = 180
9x = 180
x = 20