Question 550861: Perform the indicated operations:
-42÷6+(-7)
Found 2 solutions by jim_thompson5910, bucky:
Answer by jim_thompson5910(35256)   (Show Source):
Answer by bucky(2189) (Show Source):
You can put this solution on YOUR website! The hardest part of this problem involves understanding the order in which operations (for example: adding, subtracting, multiplying, dividing, taking exponents) are performed. The order can be remembered by PEMDAS. Use this to remind you that you do things in this general order.
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P = do the things inside parentheses first
E = work the exponents second
MD = third, reading from left to right, do the multiplications & divisions as you come to them
AS = finally, reading from left to right, do the additions & subtractions as you come to them.
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For this problem you are asked to simplify:
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-42÷6+(-7)
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This problem involves parentheses containing just the term -7. So we don't have to worry about doing any EMDAS actions inside the parentheses. However, since the parentheses are preceded by a plus sign, we can remove them, eliminate the plus sign, and leave the signs of any terms inside the parentheses unchanged. So the + (-7) becomes just -7 and the expression is simplified to:
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-42÷6-7
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There are no exponents to consider as our second step. So we can proceed to the MD (multiplications and divisions) reading from left to right, we encounter just one division sign. It tells you to divide the number just before it (-42) by the number immediately after it (6). When you do that division the answer is -7. So you can replace -42÷6 by -7 and the problems is then reduced to:
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-7 -7
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There are no more multiplications or divisions to consider. So we can proceed to the AS (additions and subtractions) in the order they are encountered in reading from left to right.
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Reading from left to right we have -7 and from that we subtract 7 (or add -7 to that, if you prefer to view it that way). The result of -7 and -7 is -14 and that is the answer to this problem:
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-42÷6+(-7) = -14
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Hope this helps to provide a little clarification to the order in which algebraic operations are taken in expressions.
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