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).

Example Input: Solve 0 = -4*v + 2*z + 18, 4 = 3*v + z - 7 for v.
Example Output: 4

Example Input: Suppose -5*j + 6*j - 5 = 0. Solve j*y - 5 = -3*u, 5*y - u = -1 - 14 for y.
Example Output: -2

Example Input: Let t(j) = -2*j - 6. Let p be t(-13). Suppose p = 3*b + 5*k, -3*k + 8*k + 55 = 2*b. Calculate the highest common divisor of 120 and b.
Example Output:
15