Question 116299
Given:
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5(2a + b) - (a + 3b)
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Do the distributed multiplication by multiplying 5 times each of the two terms in the first
set of parentheses. When you do you get:
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10a + 5b - (a + 3b)
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The second set of parentheses is preceded by a minus sign. Because of the minus sign if you
remove the parentheses you need to change the signs of the terms inside the parentheses.
When you remove these parentheses the expression becomes:
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10a + 5b - a - 3b
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Now, combine the like terms. 10a combines with -a to give 9a. And 5b - 3b combines to
give +2b. As a result, the entire expression is simplified to:
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9a + 2b
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Hope this helps you to understand the problem ... and some techniques for simplifying 
algebraic expressions.
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