Let a be the smallest integer satisfying the inequality x^2 - 15 < 2x + 7x - 40, and let b be the largest integer satisfying the same inequality. What is b-a?
x^2 - 15 < 2x + 7x - 40 rearrange as
x^2 - 9x + 25 < 0 (1)
Notice the graph here : https://www.desmos.com/calculator/5gdvkizm7m
The graph is always above the x axis (always > 0 ) so no x values make (1) true.
