1. Bell Ringer October 14, 2010 y = 7 – 2x 4x + y = 5 Step 1: Put the equations in Standard Form. 2x + y = 7 4x + y = 5 Step 2: Determine which variable to eliminate. The y’s have the same coefficient. Step 3: Add or subtract the equations. Subtract to eliminate y. 2x + y = 7 (-) 4x + y = 5 -2x = 2 x = -1

2. 2) Solve the system using elimination. Step 4: Plug back in to find the other variable. y = 7 – 2x y = 7 – 2(-1) y = 9 Step 5: Check your solution. (-1, 9) (9) = 7 – 2(-1) 4(-1) + (9) = 5 y = 7 – 2x 4x + y = 5

3. What is the first step when solving with elimination? 1. Add or subtract the equations. 2. Plug numbers into the equation. 3. Solve for a variable. 4. Check your answer. 5. Determine which variable to eliminate. 6. Put the equations in standard form.

4. Find two numbers whose sum is 18 and whose difference 22. 1. 14 and 4 2. 20 and -2 3. 24 and -6 4. 30 and 8

5. Homework: Worksheet