Mathematical question

-1X-1=+1. Minus one times minus one equals plus one. Why?

My mother used to say two wrongs don't make a right, so why do two negatives make a positive?

+1  Views: 1647 Answers: 5 Posted: 7 years ago

http://mathforum.org/dr.math/faq/faq.negxneg.html

>>> Try this link for good explanations .... here is one >>>>

Debt is a good example of a negative number. One common form of debt is a mortgage in which you owe the bank money because the bank paid for your house. It is also common for an employer to deduct a mortgage payment from an employee's paycheck to help the employee keep on schedule with the payments.

Suppose \$700 is being deducted each month to pay the mortgage. After six months, how much money has been taken out of the pay for the mortgage? We can figure out the answer by doing multiplication.

6 * -\$700 = -\$4,200

This is an illustration of a positive times a negative resulting in a negative.

Now suppose that, as a bonus, the employer decides to pay the mortgage for one year. The employer removes the mortgage deduction from the monthly paychecks. How much money is gained by the employee in our example? We can represent "removes" by a negative number and figure out the answer by multiplying.

-12 * -\$700 = \$8,400

This is an illustration of a negative times a negative resulting in a positive.

If one thinks of multiplication as grouping, then we have made a positive group by taking away a negative number twelve times.

This example may not work for you, and you might want to read others by following the related link below.

ROMOS

Now I'm lost, looking for the links below.????
lindilou

Meeps! It is above .... ABOVE!!!!
lindilou

... now it is BELOW!! The plural version is at the link... lol

Two wrongs  never make a positive. Your mother was correct.

Multiplying two negative numbers equals a positive numbernie because the negatives cancel out each other as they do in speech.

For example, if "I don't have no pencil", it means I do have a pencil. Put a pencil in one hand, leaving the other empty. The empty hand is "no pencil". When you say you don't have "no pencil", it means you don't have the empty hand, so you must have a pencil.

If you lost 3 pounds, your weight would be "-3" from normal. If you then lost 4 more pounds, "-4", your total weight loss would be 7. To lose "-7" pounds would indicate weight gain.

Multiplying negative numbers is similar.

Also, negative numbers aren't the same as two wrongs!

....same principle as when my wife comes home from shopping and claims she saved me x amount of \$ by buying her stuff on sale

....magically a minus = a plus

I hate Algebra

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