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How Do You Solve a Word Problem by Subtracting Polynomials?
A picture frame has the dimensions given in the diagram. Determine how much the longer the length is than the width. Write your answer as a polynomial in simplest form.
Summary
- The length is y2+3y+7
- The width is y-3
- Finding the difference means we are going to subtract
- Distribute the negative through the second set of parentheses
- 3y and -y are like terms
- 7 and 3 are also like terms
- 3y-y=2y
- 7+3=10
- Since there are no more like terms to combine and no parentheses, the polynomial is in simplest form

Notes
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- Remember, difference means subtraction
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- The length of the frame is y2+3y+7
- The width of the frame is y-3
- Subtracting these two polynomials will give us the difference
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- The length of the frame is y2+3y+7
- The width of the frame is y-3
- Subtracting these two polynomials will give us the difference
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- To simplify, we need to get rid of the parentheses
- We'll need to distribute the negative in front of the second set of parentheses
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- We can't get rid of the parentheses until we do this
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- Since there is no negative in front of the first set of parentheses, we don't need them
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- This means we will flip the sign of each term inside the parentheses
- So y becomes -y
- And -3 becomes 3
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- Now we can write -y+3 without parentheses
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- To get our polynomial in simplest form, we need to combine like terms
- Remember, like terms have the same variables raised to the same power
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- 3y and -y both have y raised to the first power
- So they are like terms that we can combine
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- Neither 7 nor 3 has a variable
- So they are like terms as well
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- Combine the like terms to simplify
- The like terms 3y and -y combine to make 2y
- The like terms 7 and 3 combine to make 10
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- Since there are no parentheses and no more like terms to combine, our polynomial is in simplest form