Unit 5  Objective 4  Solving 2 equations in 2 unknowns
Graphical methods are not very accurate ways to determine the common solutions of simultaneous equations. We will look at 2 algebraic methods for solving 2 equations in 2 unknowns.
Solution by Substitution
Example:

Solution by Addition or Subtraction
Add or subtract the two equations in order to eliminate one of the variables. It is sometimes necessary to multiply the original equation by a constant before you can eliminate one of the variables by adding or subtracting the equations.
Examples:

The following is an example of a verbal problem by first setting up the proper equations and then solving.
Examples:

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