Open Middle®
Directions: Using the digits 1 to 9, at most one time each, place a digit in each box to create two equations: one where x has a positive value and one where x has a negative value.
Hint
How does choosing the coefficient values affective whether the solution is positive or negative? How does choosing the constant values affective whether the solution is positive or negative?
Answer
There are many possible answers including 4x + 3 = 5x + 7 for a negative solution and 5x + 3 = 4x + 7 for a positive solution.
Source: Robert Kaplinsky