SOLUTION: Square that number and then subtract one. Divide by one less than your original number. Now subtract your original number. You reached 1 for an answer, didn’t you? How does this nu

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Square that number and then subtract one. Divide by one less than your original number. Now subtract your original number. You reached 1 for an answer, didn’t you? How does this nu      Log On


   



Question 300230: Square that number and then subtract one. Divide by one less than your original number. Now subtract your original number. You reached 1 for an answer, didn’t you? How does this number game work? (Hint: Redo the number game using a variable instead of an actual number and rewrite the problem as one rational expression). How did the number game use the skill of simplifying rational expressions? Create your own number game using the rules of algebra and post it for your classmates to solve. Be sure to think about values that may not work. State whether your number game uses the skill of simplifying rational expressions.

Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!

Start with any number (but NOT 1)

Say 73

Square that number:

73%5E2+=+73%2A73+=+5329

Subtract 1

5329+-+1+=+5328 

Divide by one less than your original number.

The original number was 73.  One less than 73 is 72.
So dividing 5328 by 72

5328%22%F7%2272%22=%2274

Now subtract your original number.

74-73+=+1

You reached 1.

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That works for all numbers. Why does it work?  

Start with any number

Say x

Square that number:

x%2Ax=x%5E2

Subtract 1

x%5E2+-+1 

Divide by one less than your original number.

The original number was x.  One less than x is x-1.
So dividing x%5E2-1 by x-1

x%5E2-1%22%F7%22x-1%22=%22

Now subtract your original number, which was x

%28x%2B1%29-x+=+x%2B1-x+=+1

You reached 1.

Notice that you could not have started with 1 because you
cannot divide by 1 less than 1 because that would be dividing
by zero!

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You can make up a rational expression with a factor in the bottom
that will cancel a factor in the top.  Say you start with this

%28%28x-2%29%28x%2B3%29%29%2F%28x%2B3%29

Then multiply the top out:

%28x%5E2%2Bx-6%29%2F%28x%2B3%29

Then to make the numerator x%5E2%2Bx-6, you say

Start with any number (other than 2).

Square it (that gives x%5E2

Add the original number (that gives x%5E2%2Bx

Subtract 6  (that gives x%5E2%2Bx-6

Divide by 2 less than the original number (that gives 

Subtract your original number  (that gives %28x%2B3%29-x=x%2B3-x=3

You reach 3.

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Try it with an arbitrary number.

Start with any number (other than 2).  Say we start with 83

Square it (that gives 83%5E2=83%2A83=6889

Add the original number (that gives 6889%2B83=6972

Subtract 6  (that gives 6972-6=6966

Divide by 2 less than the original number (2 less than 83 is 81.
6966%22%F7%2281%22=%2286

Subtract your original number  86-83=3

You reach 3.
 
You cannot start with the number 3 because you would have to
divide by 0.
 
Edwin