Definition: 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).
Input: Let w(j) = -j**3 + 5*j**2 + 9*j - 8. Let u be w(6). Let c = u + -6. Let d be (-1)/(1 + (-6)/c). Solve k = -2*f + 9, -f + d = k + 2*k for k.

-1