As the two angles are vertical angles, they are congruent, do they have the same value.
You can use an equation to find m<KNL by isolating x.
m<JNM=m<KNL
5x+2=3(x+14) Substitute by the given values
5x+2=3x+42 Subtract 3x in both sides
2x+2=42 Subtract 2 in both sides
2x=40 Divide by 2 in both sides to isolate x
x=20
Now with the result found you can find the m<KNL
m<KNL=3(20+14)
m<KNL= 102