Answer:
x = 60
Explanation:
In order to make L parallel (||) to M, you want to prove that the angles are same-side interior angles since the Same-Side Interior Angle Theorem only works for parallel lines cut by a transversal.
In order to make the angles (marked with the expressions) same-side interior angles, they have to add up to 180 degrees because they are supplementary angles.
Make an equation where the two angles add up to (equal) 180.
Combine like terms on the left side of the equation.
Divide both sides of the equation by 3.
60 is the value of x that will make L || M.