Why does it not equal a Positive
- Thread starter bobisaka
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Harry_the_cat
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The minus sign before the middle term (in the first line inside the box) should be a plus as in the original equation given. It's a typo.
Why parentheses? It is conventional to put neg numbers in parentheses when substituting into an equation. If not written as 2(-4) and just written as 2-4, it can be confused with subtraction rather than mutliplication (you could write 2 x -4 but that could be confused with the letter x). Also necessary when powers are involved because (-4)2 is different to -42.
Why parentheses? It is conventional to put neg numbers in parentheses when substituting into an equation. If not written as 2(-4) and just written as 2-4, it can be confused with subtraction rather than mutliplication (you could write 2 x -4 but that could be confused with the letter x). Also necessary when powers are involved because (-4)2 is different to -42.
HallsofIvy
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It depends upon how you have learned to think about these things. I would say that "-8" represents the number "negative 8" but that "8- 8" does not have a negative number. The "-" in "8- 8" represents the operation "subtraction". Of course some people will insist that in order to "subtract" you must "change the sign and add". Either way the result is the same.
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