It’s been a while since I’ve done geometry, but I think this is right.
Because we are dealing with a rhombus: angles X and A are the same, so we use this to solve for x like any other algebraic expression.
After we have found x (24), we can also apply the knowledge that since angles X and M are complementary they will form a 180° line when added.
Substitute the expression for angle X with the solved for expression and subtract it from 180°. And bam! Angle M