45 times 79 is 3555, but what is the answer if both 45 and 79 are negative numbers? Here we will determine if the answer to negative 45 times negative 79 is positive 3555 or negative 3555.
There are many different ways to explain and determine if the answer to negative 45 times negative 79 is -3555 or +3555 using mathematical terms such as additive inverse and mathematical laws like the Distribute Law.
We will take a different approach - process of elimination: We will simply test if -3555 is the correct answer using basic algebra.
We will test if -3555 is correct by setting up the equation negative 45 times negative 79 equals negative 3555, and then simplifying the equation to see if it is true.
(-45) (-79) = (-3555)
Divide both sides of the equation by (-79) :
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| = |
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The numerator and denominator on the left side both have (-79) which even each other out and can be removed:
| (-45) = |
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The numerator and denominator on the right side both have a minus sign (-) which even each other out and can be removed:
| (-45) = |
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A numerator of 3555 and denominator of 79 on the right side is the same as 3555 divided by 79 which is 45. Now we end up with this untrue equation:
(-45) = (45)
-45 is NOT equal to 45, thus we have proven that negative 45 times negative 79 is not equal to -3555. The answer must therefore be 3555:
-45 x -79 = 3555
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 45 times negative 79 will always have a positive answer.
Negative Times Negative Calculator
Here you can multiply another two negative numbers together.
What is negative 45 times negative 80?
Here is the next problem on our list that we have explained and calculated.
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