5x - 6 = y
2x - 3y = 4
solve the system of equations by substitution.

(-10/13, -128/13)
(14/13, -8/13)
no solution
coincident

About a day late, but... it already isolated one of the variables for you, so you can just take the first equation and substitute it into the second:

2x - 3(5x - 6) = 4
2x - 15x + 18 = 4
-13x + 18 = 4
-13x = -14
x = 14/13

based on that alone, you can see that B is your answer, but you can still plug it in to make sure:

5(14/13) - 6 = y
(70/13) - 6 = y
y = -8/13

your answer is B

2 is the least common multiple for 16 and 24 and 3 is the least common multiple for 21