Solving Linear Equations

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Solving Linear Equations
with Addition
and Subtraction
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When you do something
to one side of an equation,
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you have to do exactly
the same thing
to the other side.
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To solve an equation means
to find every number that makes the equation
true.
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In the equation,
x is the number
you add to 7
to get 15.
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What is the number?
8, of course.
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What is the number?
8, of course.
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What is the number?
8, of course.
So we would write the
solution,
.
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In some equations,
the solution is obvious.
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But in other equations,
the solution is not so obvious.
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Many times we need
a way to solve equations.
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To understand one way,
we can work backwards.
Start with a solution,
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And create another equation by changing both
sides.
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To solve that equation, you can just undo
what you did.
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To solve that equation, you can just undo
what you did.
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To solve that equation, you can just undo
what you did.
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To solve that equation, you can just undo
what you did.
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Now you see how easy solving these types of
equations can be.
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If you had started with the solution,
what would you have done to get this equation?
Hint
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And if you subtracted 12 from both sides,
what would you do to get the original solution?
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Right!
You would need to
add 12 to both sides.
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think about what you need to
do to get the variable by
itself on one side
of the equation.
As you solve these equations,
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Think about what you need to
do isolate the variable.
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