6 3 Solving Systems by Elimination Essential Question

6. 3 Solving Systems by Elimination Essential Question: How do you solve a system by elimination?

Review 1) How do you solve systems by graphing? 2) When should you solve by graphing? 3) How do you solve systems by substitution? 4) When should you solve by substitution?

Solving Systems by Elimination • The goal of elimination is to get one equation that has only one variable by “eliminating” one. • Solving by Elimination: 1) Align the system by like terms 2) Eliminate one variable by opposite terms 3) Solve for the variable left over 4) Substitute the answer into an equation and solve 5) Write the answer as (x, y) and check

Example 1

Example 1: Practice

Example 2

Example 2: Practice • If nothing eliminates, multiply one or both equations by a common factor to create an elimination.

Example 3 • Sometimes, you have to force the elimination by multiplying one or both equations by the number needed to cause an elimination.

Example 3: Practice

Word Problems • Mr. Franz has already sold 300 tickets (student & adult) for the school play. Student tickets cost $4 and adult tickets cost $6. He collected $1500. How many student tickets and how many adult tickets were sold?

Review of Systems

Summary • Answer the essential question in complete, detailed sentences. 1) How do you solve a system by elimination? • Write 2 -4 study questions in the left column to correspond to the notes.