1. Substitution Method Critical Thinking Skill: Explicitly assess information and draw conclusions Sometimes using the graphing method can be problematic. Why do you think so?

2. Substitution Method ex 1: x + y = 5 x = 1 + y Steps: 1. Solve one equation for a variable. 2. Substitute expression from Step 1 into the other equation 3. Solve for first variable 4. Plug answer into 1st equation to find the other variable 5. Write your answer as a point. 6. Check answer by plugging in both values in the other equation

3. ex 2: a - b = 45a + b = 2

4. ex 3: 3x + y = 52x - y = 10

5. ex 4: 2x + 6y = 15x = 2y