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Question

anonymous · Answer

Place the indicated product in the proper location on the grid. Write your answer in descending powers of x.

(x^2 + 2x - 1)(x^2 + 2x + 5)

ranga · Answer

I am guessing you will have to write it as follows:


         x^2     +2x        +5
x^2   x^4     +2x^3    +5x^2
2x                +2x^3    +4x^2      +10x
-1                               -x^2        -2x       -5

Add the columns (without including the top row)

anonymous · Answer

Wait so are you saying that -1 - x^2 - 2x - 5 is the answer?

ranga · Answer

No.  Leave the left most column and the top row.
Then add up the columns.

anonymous · Answer

Okay so x^2+x^6+6x^6+13x^6+8x-5?

ranga · Answer

Where do you get x^6 from?  
Ignore the top row,  Ignore the first column.  
Then add each column and put the answer at the bottom:

x^4 + 4x^3 + 8x^2 + 8x - 5

anonymous · Answer

So I just leave the exponents alone? Like with the 2x^3 + 2x^3 You just make it 4x^3?

ranga · Answer

Yes.  You add and subtract like terms.  We are not multiplying or dividing which will change the exponents.  Addition and subtraction will not affect the exponents.
For example:
10x^4 + 3x^2 + 2x^4 + 6x^2 = (10x^4 + 2x^4) + (3x^2 + 6x^2) = 12x^4 + 9x^2

anonymous · Answer

Ok. So the answer is just x^4 + 4x^3 + 8x^2 + 8x - 5?

ranga · Answer

yes.