The value of y can be calculated by translating the equation such that we solve y in terms of x.
-3x - 8y = 10
-8y = 10 + 3x
y = (10 + 3x) / -8
Then, we substitute 2 to the x in the equation.
y = (10 + 3(2)) / - 8 = 16/-8
y = -2
Thus, the value of y in the equation is -2.