1. Choosing the Best Method
Lesson 27
Linear Equations
Choosing the Best Method

2. Warm-Up Solve one of the systems below using any method. Explain
why you chose your method.
y = 5x – 4 x + 2y = 25
2x + 7y = 1 –2x + 2y = –10
y = x – 4 y = –3x + 3

3. Choosing the Best Method
Target:
Choose the best method for solving
a given system of equations.

5. Choosing a Method to Solve a System of Linear Equations
Graphing: Both equation are in slope-intercept form.
Tables: Both equations are in slope-intercept form and the slope is an integer.
Substitution: A variable is isolated in one equation.
Elimination: Both equations are in standard form and the variables are lined up in columns.

6. Example 1a Choose the best method to solve the system of equations.
Explain your reasoning.
x – 2y = 10
3x + 2y = 6
Elimination
The y-variable will easily be eliminated.

7. Example 1b Choose the best method to solve the system of equations.
Explain your reasoning.
y = 2x – 3
4x – 5y = –1
Substitution
The first equation is already solved for y.

8. Example 1c Choose the best method to solve the system of equations.
Explain your reasoning.
y = x
y = 2x + 7
Graphing
The equations are already in slope-intercept form.

9. Example 1d Choose the best method to solve the system of equations.
Explain your reasoning.
y = 5x – 9
y = 2x – 3
Tables
The equations are already in slope-intercept form and the slopes are integers.

10. Exit Problems Write a sample of a system of equations that
would be best solved by…
elimination
graphing
substitution

11. Communication Prompt
Choose one method for solving a system of equations. Describe how the equations might be set up that would allow you to solve with your method easily.