instruction:
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).
question:
Solve -2*i = -4*x + 1 - 17, 5*i = 5*x + 20 for i.
answer:
0


question:
What comes next: -37, -72, -129, -220, -357, -552, -817?
answer:
-1164


question:
Suppose -25 = -3*c + 29. What is the highest common factor of 18 and c?
answer:

18