Intermediate · 12 min
Understanding inequalities
Solve inequalities and interpret which values meet a limit.
Keep the direction for addition
An inequality compares values rather than making them equal. Adding or subtracting the same amount on both sides keeps its direction.
Worked example
x + 3 < 8 means x < 5.
Reverse when multiplying by a negative
Multiplying or dividing both sides by a negative number reverses the inequality sign. Distinguish strict inequalities from ones that include equality.
Worked example
−2x < 6 means x > −3.
Describe a spending limit
- Write an inequality for buying x items at 4 each with a delivery fee of 3 and a budget of 23.
- Find the maximum whole number of items you can buy.