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Objective
Know how to solve equations with 1 variable
Example
Solve for y.
-44 ÷ y = 4
Answer: y = -11
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Explanation
Solving for a variable is a skill that gets easier with practice.
The problem many students have is that they forget where they are going. Keep your goal in mind when solving
Your goal is to isolate the variable
This means that the variable is:
Alone on one side of the equal sign, with no other numbers
Not negative
How do you achieve this?
perform opposite operations to cancel out numbers you don't want
-44 ÷ y = 4
We can't have y with a ÷ sign in front of it, so let's cancel it out by multiplying by y. Remember, whatever you do to one side of the equation, you must also do to the other side.
-44 ÷ y = 4
x y x y
Now, x y and ÷ y cancel to 1,so
-44 x 1 = 4 x y
-44= 4y
y is now almost alone, but it has that pesky 4 in front of it. Since 4y is the same thing as y x 4, let's cancel out the x 4 with ÷ 4.
-44 = 4y
÷ 4 ÷ 4
Now, 4 ÷ 4 = 1 so
-11 = y
Answer: -11
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Examples
Example 1
a x 7 = 28
a x 7 = 28
÷ 7 ÷7
a = 4
Answer: 4
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Example 2
j ÷ 2 = 0
j ÷ 2 = 0
x 2 x 2
j = 0
Answer: 0
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Example 3
-8 = 9 + c
-8 = 9 + c
-9 -9
-17 = c
Answer: -17
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Example 4
-8 = 9 - c
-8 = 9 - c
-9 -9
-17 = -c
-17 = -c
x(-1) x(-1)
17 = c
Answer: 17
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Practice your skills
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Ready?
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