Solving One-step Equations Algebraically

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Solving One-step Equations Algebraically
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• Today, we will connect modeling equations with
  algebra tiles to solving equations algebraically.
  
• Our goal and rule for solving equations, however,
  have not changed.

The goal of solving equations -To get one x
alone on one side of the equation.
The rule for solving equations -Do the same
thing to both sides of the equation.
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Lets start with an addition equation x 2
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With algebra tiles
Algebraically
x 2 7

• To get x alone, take 2 units from each side.
• In math, take away means to subtract.

- 2 - 2
x 5
Think opposite operations To undo x plus 2,
we subtracted 2.
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Lets try a multiplication equation 3x 15
With algebra tiles
Algebraically
3x 15

• To get x alone, split both sides into 3 groups.
• In math, splitting into groups means to divide.

3 3
x 5
Think opposite operations To undo 3 times x,
we divided by 3.
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Now for a subtraction equation x 3 8
With algebra tiles
Algebraically
x 3 8 x -3 8
x 3 8

• To get x alone, add 3 units to both sides.
• In math, adding 3 means 3.

3 3
x 11
Think opposite operations To undo x minus 3,
we added 3.
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We did not model a division equation. Based on
the previous examples, can you guess what will
happen? How will we undo division?
Algebraically
We will use multiplication to undo
division. In this case, we will multiply both
sides by 5.
(5) (5)
x 20
Think opposite operations To undo x divided
by 5, we multiplied by 5.