For parallelogram lmno, if m∠l = 3x - 25 and m∠n = 2x - 10, find m∠m.

160
115
35
20

In a parallelogram opposite angles are congruent, that means:

Angle L = Angle N, replace L & N by they respective value, then

3x-25 = 2x-10 ==> x=15 , Now plug the value of x in any of the 2 sides
3(15) -25 =20°

hence Angle L =- Angle N = 20°

Now let's calculate Angle M. In a parallelogram the adjacent angle are supplementary, that means their sum = 180°, then

Angle N + Angle N = 180°==> Angle M = 180°-20° = 160°