Many real-world situations can be approached by developing a model, writing an equation, and solving it. You can use algebra tiles to solve equations. The green tile represents the variable, x.
Example
1.
Use
algebra tiles to solve each equation.
x + (–2) = –7
Alternative Solutions :
Step 1
Model x + (–2) = –7 by placing 1 green tile and
2
red
square tiles on one side of the mat to
represent x + (–2).
Place 7 red square tiles on the
other side to represent –7.
Step 2
To get the green tile by itself, remove
2 red
square tiles from each side.
Step 3
The green tile on the left side of the
mat is matched
with 5 red square tiles.
Therefore, x = –5.
2.
x – 3 = 5
Alternative Solutions :
Step 1
Write the equation in the form x + (–3) = 5. Place
green tile and 3 red square tiles on one side of the mat
to represent x + (–3).
Place 5 yellow square tiles on the
other side of the mat to represent +5.
Step
2 To get the green tile by itself, you need to remove 3
red square tiles from each side.
Since there are no
red square tiles on the right side of
the mat, you
will need to add 3 yellow square
tiles to each side to
make 3 zero pairs on the left side of
the mat.
Step 3 Remove
the zero pairs.
Step 4 The green
tile is matched with 8 yellow square tiles.
Therefore, x = 8.
In Examples 1 and 2, you solved each equation for the
variable by isolating the variable on one side of the equation.
Example
Zoology Link
3. The
largest bear is the Alaskan brown bear. When fully grown, it has a height of 9
feet. The smallest bear is the sun bear. The Alaskan brown bear is 6 feet
longer than the sun bear. Find the length of the sun bear.
Alternative Solutions :
Explore
You know that the Alaskan brown
bear is 6 feet
longer than the sun bear. You need to find the length
of the sun bear.
Plan Let x represent the length of the sun bear. Translate the
problem into an equation using the variable x.
Model the equation and then solve.
Solve
To solve for x,
subtract 6 from each side.
The solution is 3. So, the length of the sun bear is 3 feet.
Examine Check
the solution.
The length of the Alaskan brown bear
is equal to the length
of the sun bear plus 6 feet. The
length of the sun bear is 3 feet,
and 3 feet plus 6 feet is 9 feet.
The answer is correct.
Sumber
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