39 times 85 is 3315, but what is the answer if both 39 and 85 are negative numbers? Here we will determine if the answer to negative 39 times negative 85 is positive 3315 or negative 3315.
There are many different ways to explain and determine if the answer to negative 39 times negative 85 is -3315 or +3315 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 -3315 is the correct answer using basic algebra.
We will test if -3315 is correct by setting up the equation negative 39 times negative 85 equals negative 3315, and then simplifying the equation to see if it is true.
(-39) (-85) = (-3315)
Divide both sides of the equation by (-85) :
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| = |
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The numerator and denominator on the left side both have (-85) which even each other out and can be removed:
| (-39) = |
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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:
| (-39) = |
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A numerator of 3315 and denominator of 85 on the right side is the same as 3315 divided by 85 which is 39. Now we end up with this untrue equation:
(-39) = (39)
-39 is NOT equal to 39, thus we have proven that negative 39 times negative 85 is not equal to -3315. The answer must therefore be 3315:
-39 x -85 = 3315
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 39 times negative 85 will always have a positive answer.
Negative Times Negative Calculator
Here you can multiply another two negative numbers together.
What is negative 39 times negative 86?
Here is the next problem on our list that we have explained and calculated.
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