Given a simple high-school level math question, you are required to solve it and provide the final answer. The final answer is always a single number. These questions can range from a variety of topics like simple arithmetic, solving equations, converting a quantity from one unit to another, finding remainders/GCD/LCM, finding probabilities etc. Each question has only one correct answer. This answer can be a positive or negative integer, a fraction or a decimal number. If the answer is a negative number use the hyphen (e.g. -42) symbol for the minus sign. For decimal numbers, do not add extra zeros after the decimal point. For fractional numbers, separate the numerator and denominator using a forward slash (e.g. 3/25).

Let r = 4 - 8. Let p = r - -4. Suppose c + 2*x - 82 = -3*c, 4*c + 5*x - 97 = p. What is the units digit of c?
8

Solve -5*i - 5*r - 50 = 0, -r + 5 = -4*i - 10 for i.
-5

Let o = 1 + 4. Let i = o - 3. Solve -2*x + 2 = -3*x - 5*z, x + i = -2*z for x.

-2