Warm Up 1) Is (-3, 4) a solution to the system?

2) Solve the system by graphing y = -2x + 5 2y = x - 2

HW Check 7.1

Recall from yesterday:Definitions

System of Equations: A set of two or more equations that use the same variable.

Solution to a System: A set of values that that makes ALL equations true.

Solving Systems by Substitution

Substitution

Not every system can be solved easily by graphing. Sometimes it is not always clear from the graph where the solution is.

We can use an algebraic method called SUBSTITUTION to find the exact solution without a graphing calculator.

Step 1: Solve for one of the variables.

Step 2: Substitute the expression of the equation you solved for into the other equation.

Step 3: Solve for the variable.

Step 4: Substitute the value of x into either equation and solve.

Example #1Solve the system by substitution.

Example #2Solve the system by substitution.

Example #3Solve the system by substitution.

Example #4Solve the system by substitution.

Example #5Solve the system by substitution.

Example #6Solve the system by substitution.