Open Middle®
Directions: Using the digits 0 to 9, at most two times each, place a digit in each box to make the equations true.
Hint
Think about the slope between those points compared to the slope of the function.
Answer
There are many answers. One is a function of 3x^2+5, where f(8)-f(6) / 8-6 = 42
Source: Owen Kaplinsky