Basic Algebra/Solving Equations/Solving Equations with Addition and Subtraction

Vocabulary

Lesson

Zoey and Pual put three eggs on each side of a scale. When Zoey took an egg away on one side the scale, it tipped. When Pual took an egg from the other side of the scale it balanced again. The same thing can be used in math too.

What is y in this equation?

2 + y = 7

We want to know what Y is, so we want to make Y by itself on one side of the equal sign.

2 + y = 7

First subtract 2 from both sides.

2-2 + y = 7-2

After we subtracted, Y is by itself and we can see that y equals

y = 5

Example Problems

ex1. (3 + x) -4 = 4 add 4 to each side to get rid of the -4

                                                     (3 + x) -4 +4 = 4 +4
                                                     (3 + x) = 8

because there is only one operation to be done on the left of the equation you can get rid of ()

                                                      3 + x = 8

Subtract 3 from each side of the equation

                                                      3 + x -3 = 8 -3
                                                      x = 5

Practice Games

put links here to games that reinforce these skills

Practice Problems

(Note: put answer in parentheses after each problem you write)

1. x + 1 = 4 (3) 2. x - 1 = 4 (5)