9 times 51 is 459, but what is the answer if both 9 and 51 are negative numbers? Here we will determine if the answer to negative 9 times negative 51 is positive 459 or negative 459.
There are many different ways to explain and determine if the answer to negative 9 times negative 51 is -459 or +459 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 -459 is the correct answer using basic algebra.
We will test if -459 is correct by setting up the equation negative 9 times negative 51 equals negative 459, and then simplifying the equation to see if it is true.
(-9) (-51) = (-459)
Divide both sides of the equation by (-51) :
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| = |
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The numerator and denominator on the left side both have (-51) 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 459 and denominator of 51 on the right side is the same as 459 divided by 51 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 51 is not equal to -459. The answer must therefore be 459:
-9 x -51 = 459
The above applies to all math problems where you multiply two negative numbers. Multiplying two negative numbers such as negative 9 times negative 51 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 52?
Here is the next problem on our list that we have explained and calculated.
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