5.5 (Applying Systems of Linear Equations) ~ Notes and Homework
KEY CONCEPT
Solving Systems of Equations
The Best Time to Use
Method
Graphing
Substitution
Elimination Using Addition
Elimination Using Subtraction
Elimination Using Multiplication
To estimate the solution, since graphing
usually does not give and exact solution
If one of the variables in either equation has a
coefficient of 1 or -1 {or is already
ISOLATED FOR YOU!}
If one of the variables has opposite coefficients
in the two equations
If one of the variables has the same coefficient
in the two equations
If none of the coefficients are 1 or -1 and
neither of the variables can be eliminated by
simply adding or subtracting the equations
Determine the best method to solve each system of equations. Then solve the system.
1. 𝑥 = 2𝑦 + 1
3𝑥 + 𝑦 = 17
2.
3. 4𝑥 + 2𝑦 = 12
−4𝑥 + 5𝑦 = −5
4.
7𝑥 + 5𝑦 = 29
21𝑥 − 25𝑦 = −33
𝑥 + 3𝑦 = −14
𝑥 + 2𝑦 = −10
5. You buy 6 videos on sale. The videos are on sale for $8 and $10. You spend $52. How many
$8 videos did you buy?