SOLUTION: A well-known fact is that a negative number multiplied by a negative number yields a positive number, or, in other words, that (−1)(−1)=1. When asked to justify this, three stu

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: A well-known fact is that a negative number multiplied by a negative number yields a positive number, or, in other words, that (−1)(−1)=1. When asked to justify this, three stu      Log On

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Question 1169801: A well-known fact is that a negative number multiplied by a negative number yields a positive number, or, in other words, that (−1)(−1)=1. When asked to justify this, three students reasoned as follows:
Student 1:
" Take the number line. Subtracting the smaller from the larger should give us the distance between two numbers. Now consider 0 and −1 on the number line.
The distance between them should be 1. So we have that
0−(−1)=1⟹−(−1)=1⟹(−1)(−1)=1
This proves the claim."

Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52776) About Me  (Show Source):
You can put this solution on YOUR website!
.

G I B B E R I S H


Never post such gibberish to the forum.


I will delete it EVERY TIME as I see it - exactly in a way as I did it this time.



            Why ? - - - Simply because this forum is not a psychic clinic.




Answer by greenestamps(13198) About Me  (Show Source):
You can put this solution on YOUR website!


(1) Your post only shows the response by one of the three students.

(2) There is no question in your post.

(3) The argument shown for the one student involves subtraction; it has nothing to do with multiplication.

Re-post your problem, showing all the given information, and asking an actual question.