2. Solving Systems by Substitution (isolated) 3/16/2016 Objective: solve a linear system by substitution when a term is already isolated. Students will solve a system of two linear equations in two variables algebraically and are able to interpret the answer graphically. Students are able to solve a system of two linear inequalities in two variables and to sketch the solution sets.

3. Yesterday’s Homework 1.Any questions? 2.Please pass your homework to the front. Make sure the correct heading is on your paper. Is your NAME on your paper? Make sure the homework is 100% complete. Incomplete work will NOT be accepted.

4. Introduction To solve a linear system by ___________ first _______ the isolated variable in one of the equations. Next plug that expression into the other _________ to find the value of one variable. Finally plug that solution into any of the original _________ to find the other variable. substitution identify equations

5. Notes Solving a System of Equations by Substitution 1. Solve one of the equations for x or y. 2. Substitute your new expression from Step 1 into the other equation and solve for the variable. 3. Plug that solved variable into the other equation from Step 1 and solve for the other variable. 4. Check your answers by plugging it into the original equations. - Get x or y by itself.

6. Notes Ex. Solve the system by substitution. 2) Substitute into other equation. 3) Plug in answer into other equation. 4) Check answer! 1) Solve for x or y. The variable x is already by itself.

7. Notes Ex. Solve the system by substitution. 2) Substitute into other equation. 3) Plug in answer into other equation. 4) Check answer! 1) Solve for x or y. The variable y is already by itself. Now you try.

8. Notes Ex. Solve the system by substitution. 2) Substitute into other equation. 3) Plug in answer into other equation. 4) Check answer! 1) Solve for x or y. The variable x is already by itself.

9. Notes Ex. Solve the system by substitution. 2) Substitute into other equation. 3) Plug in answer into other equation. 4) Check answer! 1) Solve for x or y. The variable y is already by itself. Now you try.

10. Notes Ex. Solve the system by substitution. 2) Substitute into other equation. 3) Plug in answer into other equation. 4) Check answer! 1) Solve for x or y. The variable y is already by itself. Step 3

11. Notes Ex. Solve the system by substitution. 2) Substitute into other equation. 3) Plug in answer into other equation. 4) Check answer! 1) Solve for x or y. The variable x is already by itself. Step 3 Now you try.

12. Notes Ex. Solve the system by substitution. 2) Substitute into other equation. 3) Plug in answer into other equation. 4) Check answer! 1) Solve for x or y. The variable x is already by itself. Step 3

13. Notes Ex. Solve the system by substitution. 2) Substitute into other equation. 3) Plug in answer into other equation. 4) Check answer! 1) Solve for x or y. The variable y is already by itself. Step 3 Now you try.

14. Notes Ex. Solve the system by substitution. 2) Substitute into other equation. 3) Plug in answer into other equation. 4) Check answer! 1) Solve for x or y. The variable y is already by itself. Step 3

15. Notes Ex. Solve the system by substitution. 2) Substitute into other equation. 3) Plug in answer into other equation. 4) Check answer! 1) Solve for x or y. The variable y is already by itself. Step 3 Now you try.

16. Class Work Solve the system by substitution.

17. p408 #18-30 (even only) Today’s Homework 1.Pencil ONLY. 2.Must show all of your work. NO WORK = NO CREDIT 3.Must attempt EVERY problem. 4.Always check your answers. Rules for Homework