Work out compound inequality instantly with clear inputs, formula shown and shareable results.
A compound inequality is solved by applying the same operation to all three parts at once. If the coefficient is negative both inequalities reverse, which swaps which endpoint is the lower one.
Compound inequality
p < ax + b < q ⇒ (p − b)/a and (q − b)/a are the endpoints, ordered by the sign of a
Add 2 to get 3 < 3x < 15, then divide by 3 to get 1 < x < 5.
Both comparisons flip, so the endpoints swap places; the calculator orders them for you.