Answer:
4th one is correct for x/y
Step-by-step explanation:

Apply Quoteint of Powers. Divide the intergers. serpately.
Note that Quotient of Powers is

So the answer is

The answer is

or

Because all angles adds up to 180 we are going to add the equations and equal it to 180.
5x - 3 + 4x - 7 + x = 180
5x + 4x + x - 3 - 7 = 180
10x - 10 = 180
10x = 180 + 10
10x / 10 = 190/10
x = 19 degrees
5x - 3
5(19) - 3 = 92 degrees
4x - 7
4(19) - 7 = 69 degrees
angle L = 92 degrees
angle M = 69 degrees
angle N = 19 degrees