7th Grade Math · Unit 3
Combine like terms to write a simpler expression.
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Like terms
Like terms have the same variable and the same power. Numbers combine with numbers.
4y and y are like terms. 4y and 4y² are not. 3m and 3n are not.
Keep the sign with the term
The sign in front of a term belongs to that term. Add the coefficients and keep the variable.
6y − 2y = 4y.
One term for each kind
Write one term for each variable, then the number term if there is one.
If a group adds to 0, leave that group out. If every term cancels, the expression is 0.
Perimeter of an L
The long side equals the two shorter sides that run the same way.
Subtract to find an unlabeled side. Then add all six sides.
Add and subtract terms that use the same variable.
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Combine each variable on its own. Then combine the numbers.
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Find unlabeled sides, then add.
Missing height = long side − short side
(4c + 1) − (2c + 1)
2c
Missing width = long side − short side
(4c + 2) − 3c
c + 2
Perimeter = the sum of all six sides
Answer:
Missing height = long side − short side
(4x + 3) − (x + 3)
3x
Missing width = long side − short side
(5x + 4) − 3x
2x + 4
Perimeter = the sum of all six sides
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Missing height = long side − short side
(4y + 3) − (3y + 2)
y + 1
Missing width = long side − short side
(5y + 6) − 4y
y + 6
Perimeter = the sum of all six sides
Answer:
Missing height = long side − short side
(4n + 4) − (n + 4)
3n
Missing width = long side − short side
(3n + 4) − (2n + 3)
n + 1
Perimeter = the sum of all six sides
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Missing height = long side − short side
(4a + 5) − 2a
2a + 5
Missing width = long side − short side
(6a + 2) − 5a
a + 2
Perimeter = the sum of all six sides
Answer:
Missing height = long side − short side
(4m + 4) − 3m
m + 4
Missing width = long side − short side
(3m + 3) − (m + 2)
2m + 1
Perimeter = the sum of all six sides
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Missing height = long side − short side
(4p + 3) − (p + 2)
3p + 1
Missing width = long side − short side
(4p + 4) − (2p + 1)
2p + 3
Perimeter = the sum of all six sides
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Missing height = long side − short side
(3t + 3) − (2t + 3)
t
Missing width = long side − short side
(7t + 5) − 6t
t + 5
Perimeter = the sum of all six sides
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Missing height = long side − short side
(3w + 6) − (w + 5)
2w + 1
Missing width = long side − short side
(5w + 2) − (3w + 2)
2w
Perimeter = the sum of all six sides
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Missing height = long side − short side
(4b + 2) − (3b + 2)
b
Missing width = long side − short side
(5b + 4) − (4b + 1)
b + 3
Perimeter = the sum of all six sides
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Missing height = long side − short side
(5k + 5) − (2k + 4)
3k + 1
Missing width = long side − short side
(5k + 7) − (k + 7)
4k
Perimeter = the sum of all six sides
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