68 times 85 is 5780, but what is the answer if both 68 and 85 are negative numbers? Here we will determine if the answer to negative 68 times negative 85 is positive 5780 or negative 5780.
There are many different ways to explain and determine if the answer to negative 68 times negative 85 is -5780 or +5780 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 -5780 is the correct answer using basic algebra.
We will test if -5780 is correct by setting up the equation negative 68 times negative 85 equals negative 5780, and then simplifying the equation to see if it is true.
(-68) (-85) = (-5780)
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:
| (-68) = |
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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:
| (-68) = |
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A numerator of 5780 and denominator of 85 on the right side is the same as 5780 divided by 85 which is 68. Now we end up with this untrue equation:
(-68) = (68)
-68 is NOT equal to 68, thus we have proven that negative 68 times negative 85 is not equal to -5780. The answer must therefore be 5780:
-68 x -85 = 5780
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 68 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 68 times negative 86?
Here is the next problem on our list that we have explained and calculated.
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