Today your child learns the final method of solving for two variables when given two independent equations. This is called Elimination by Addition and Subtraction. The basic idea is to set up the equations so that you can either add or subtract them from (or to) each other and eliminate one of the variables. DoodlePoodle takes your child through an example and now that your child has is on her third method for solving this type of problem, she should have an easy time of it.

Download Lesson 121 of Doodles Do Algebra HERE

Answers:

1. There is even a hint here to have your child try multiplying the first equation by a “2”. That gives a -2y term in the first equation and a 2y term in the second equation and when you add the two equations together, you get an equation that only contains x’s and then she can use the methods she learned for solving a simple equation with one variable to find the value of x…. and you get the idea by now. So x=4 and y=5.

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