1. Answer these:  1. If two lines intersect, how many solutions exist?  2. If a system of two linear equations has no solution, what is true of their graphs?  3. Solve by substitution. (2, 2) one Parallel Lines

2. More Substitution Method Coordinate Algebra Standard: A.REI.5

3. Essential Question  How do I solve a system of equations using the substitution method?

4. Substitution Method  Algebraic method used to solve a system of equations for an exact solution.  Use substitution property of equality to help you find the values of (x, y).  Remember, one equation in the system needs to be written as either x= or y= for this method.

5. Ex. 1)  Solve by substitution.  Answer: no solution

6. Ex. 2)  Solve by substitution.  Answer: Infinitely many solutions

7. Summarizer  Describe how to use substitution to solve the following system of linear equations.

8. T.O.t.D  How many solutions do the following systems have? Use the substitution method to help you decide. NO SolutionInfinite Solutions