9 times 69 is 621, but what is the answer if both 9 and 69 are negative numbers? Here we will determine if the answer to negative 9 times negative 69 is positive 621 or negative 621.
There are many different ways to explain and determine if the answer to negative 9 times negative 69 is -621 or +621 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 -621 is the correct answer using basic algebra.
We will test if -621 is correct by setting up the equation negative 9 times negative 69 equals negative 621, and then simplifying the equation to see if it is true.
(-9) (-69) = (-621)
Divide both sides of the equation by (-69) :
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| = |
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The numerator and denominator on the left side both have (-69) which even each other out and can be removed:
| (-9) = |
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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:
| (-9) = |
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A numerator of 621 and denominator of 69 on the right side is the same as 621 divided by 69 which is 9. Now we end up with this untrue equation:
(-9) = (9)
-9 is NOT equal to 9, thus we have proven that negative 9 times negative 69 is not equal to -621. The answer must therefore be 621:
-9 x -69 = 621
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 9 times negative 69 will always have a positive answer.
Negative Times Negative Calculator
Here you can multiply another two negative numbers together.
What is negative 9 times negative 70?
Here is the next problem on our list that we have explained and calculated.
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