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 -4*f = 3*o - 3 + 4, 2*o - 3*f - 5 = 0 for o.
Example Output: 1

Example Input: Solve -12*b = -35*b + 92 for b.
Example Output: 4

Example Input: Solve 7 = 4*a + 19 for a.
Example Output:
-3