Check Your Skills
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Does |−5 | + |5| + |−5| = |15|?
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If 4y − (x − 4) = 4x + (−y + 4), and neither x nor y = 0, what is
A double negative occurs when a minus sign is in front of a negative number (which already has its own negative sign). For example:
What is 7 − (−3)?
Subtracting a negative number is equivalent to adding the corresponding positive number:
7 − (−3) = 7 + 3 = 10.
This is a very easy step to miss, especially when the double negative is somewhat hidden. For instance:
What is 7 − (12 − 9)?
Many people will make the mistake of computing this as 7 − 12 − 9 = −14. However, notice that the second term in the expression in parentheses has a double negative. Therefore, this expression should be calculated as 7 − 12 + 9 = 4.
Does |−5 | + |5| + |−5| = |15|?
If 4y − (x − 4) = 4x + (−y + 4), and neither x nor y = 0, what is