The law of cosines is:
c² = a² + b² - 2abCos(C)
Therefore, in order to apply this law, we must know the value of two adjacent sides, represented by a and b here, and the value of their subtended angle, represented by C.
-502.5 - 115 = - 617.5
63 1/4 - 2 1/5 =
63 - 2 = 61
1/4 - 1/5 = 5/20 - 4/20 = 1/20
so 63 1/4 - 2 1/5 = 61 1/20
after the sub dove, elevation level is - 617.5 and temp is 61 1/20 F
Distance formula:

5 units-4.5 units=0.5 units
LM is 0.5 units longer than LM.
1.5x + 0.2y = 2.68....multiply by 0.3
1.6x + 0.3y = 2.98...multiply by - 0.2
------------------------
0.45x + 0.06y = 0.804 (result of multiplying by 0.3)
- 0.32x - 0.06y = - 0.596 (result of multiplying by - 0.2)
----------------------add
0.13x = 0.208
x = 0.208/0.13
x = 1.6
1.5x + 0.2y = 2.68
1.5(1.6) + 0.2y = 2.68
2.4 + 0.2y = 2.68
0.2y = 2.68 - 2.4
0.2y = 0.28
y = 0.28/0.2
y = 1.4
solution (they intersect at) (1.6,1.4)