1. Section 6.1 Solving Inequalities Using Addition or Subtraction
Goal: Solve & graph one-step inequalities in one variable
using addition or subtraction.

2. Inequalities– An expression stating that two algebraic expressions are not necessarily equal.
> greater than
< less than
≤ less than or equal
≥ greater than or equal
≠ not equal to
Gets an open circle ○
Gets a closed circle ●

5. Solve by Adding
Solve s – 12 > 65. Check your solution.
s – 12 > 65 Original inequality
s – > Add 12 to each side.
s > 77 Simplify.
Check To check, substitute 77, a number less than 77, and a number greater than 77.
Answer: The solution is the set {all numbers greater than 77}.

7. Solve by Subtracting
TEMPERATURE By 5:00 P.M. the temperature in Fairbanks had risen 23 degrees to a temperature that is now less than 14°F. What was the temperature at the beginning of the day?
t < 14 Original inequality
t + 23 – 23 < 14 – 23 Subtract 23 from each side.
t < –9 Simplify.
Answer: The solution set is {x | x < –9}.

8. Homework Assignment #29
6.1 Practice A Sheet