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Question 604865: Hello,
would you pls check if my answer is correct?
Subtract and simplify: (2x^2 + 5x – 4) – (3x^2 – 7x + 1)
My answer : –x^2 + 12x – 5
Thanks a lot,
H.H
Answer by bucky(2189)   (Show Source):
You can put this solution on YOUR website! Your answer is correct.
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Because the first set of parentheses is preceded by an implied + sign, the parentheses can be removed without changing the terms inside. So after removing the first set of parentheses the problem simplifies to:
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2x^2 + 5x - 4 - (3x^2 - 7x + 1)
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In this simplified version of the problem, the set of parentheses is preceded by a - sign. Therefore, you can remove the parentheses if you also change the sign of every term within the parentheses. So when you remove the parentheses, the problem now simplifies to:
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2x^2 + 5x - 4 - 3x^2 + 7x - 1
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Now group all terms having like powers of x as follows:
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2x^2 - 3x^2 + 5x + 7x - 4 - 1
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and then combine each pair of the like terms and you have:
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-x^2 + 12x - 5
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This is exactly as you said it should be.
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Good job and keep up the good work. I hope this gives you confidence that you understand what to do with problems such as this one.
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