document.write( "Question 453160: can you explain how multiplying or dividing a negative by a negative equals a positive \n" ); document.write( "
Algebra.Com's Answer #311368 by solver91311(24713)![]() ![]() You can put this solution on YOUR website! \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Imagine that you have a number line large enough for you to walk on, and like one of the X-men, you have the ability to stretch your limbs as far as you like so that you can take as long of steps as you like.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now, let's define the operation of multiplication of two numbers, call them \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "For example, let's say that you want to multiply 2 times 3. You would take 2 steps each of which was 3 units long. If you started at zero, you would end up at six.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So far, so good, right? Now let's add a little more to the definition of multiplication to take care of signed numbers.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Lets say that the sign on the first number is the direction you start out facing. So if you have a positive \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So if you multiply +2 times +3, you face toward the positive and walk forward, making you end up on +6. (Plus times Plus is Plus)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If you multiply -2 times +3, you face toward the negative and walk forward, making you end up on -6. (Minus times Plus is Minus)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If you multiply +2 times -3, you face toward the positive but you walk backwards, making you end up on -6. (Plus times Minus is Minus)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Finally, if you multiply -2 times -3, you face the negative and walk backwards making you end up on +6. (Minus times Minus is Plus)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Consider the double negative analogy from English:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "I have a pencil. (Positive that you have, and positive existence of a pencil)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "I don't have a pencil. (Negative that you have, and positive existence of a pencil)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "I have no pencil. (Positive that you have, but negative existence of a pencil)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "I don't have no pencil. (Negative that you have, and negative existence, hence you must have at least one pencil -- or all of the pencils in existence. If you do not have NO pencil, then you must have SOME pencil)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "John \n" ); document.write( " \n" ); document.write( "My calculator said it, I believe it, that settles it \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " |