Solve equations using addition and subtraction

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y = 10

10 + (-3) = 7

Draw “the river” to separate the equation into 2 sides

Eliminate the double sign

Add 3 to both sides

Simplify vertically

Check your answer by substituting your answer back into the problem

Slide 11

5) Solve. -x - (-2) = 1

-x + 2 = 1

- 2 - 2

-x = -1

x = 1

-(1) + 2 = 1

Draw “the river” to separate the equation into 2 sides

Eliminate the double sign

Subtract 2 from both sides

Simplify vertically

We haven’t gotten x by itself. If we read this aloud, it is “the opposite of x equals -1”. What would x be equal?

Check your answer

Slide 12

Solve -y – (-3) = 7

y = 10

y = 4

y = -10

y = -4