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Mathematics 24 Online
OpenStudy (anonymous):

Find the product and enter it in the box below. Enter your answer as a polynomial in descending order and use the caret (^) for exponents. For example, you would write as 4x^2. (2x2 + 10)(5 - x2)

OpenStudy (sleepyjess):

Do you know how to start this?

OpenStudy (anonymous):

no not at all

OpenStudy (sleepyjess):

Are you familiar with the FOIL method?

OpenStudy (anonymous):

no

OpenStudy (sleepyjess):

Here is what FOIL stands for: F - multiply the first terms of the binomials O - multiply the outside terms of the binomials I - multiply the inside terms of the binomials L - multiply the last terms of the binomials

OpenStudy (sleepyjess):

So we have \(\sf (2x^2~+~10)(5~-~x^2)\) right?

OpenStudy (anonymous):

yes

OpenStudy (sleepyjess):

Ok so the first part of the FOIL method is multiply the first terms. The first terms of the 2 binomials are \(\sf 2x^2\) and \(\sf 5\)

OpenStudy (anonymous):

10^2 ?

OpenStudy (sleepyjess):

Close, \(\sf 10x^2\)

OpenStudy (sleepyjess):

What do you think the outside terms will be?

OpenStudy (anonymous):

ok

OpenStudy (anonymous):

next?

OpenStudy (sleepyjess):

What do you think the outside terms will be?

OpenStudy (anonymous):

wat i do to find it

OpenStudy (sleepyjess):

The outside terms are going to be \(\sf 2x^2\) and \(\sf x^2\). What does that equal when they are mutliplied?

OpenStudy (anonymous):

3x^4

OpenStudy (sleepyjess):

Almost, it should be \(\sf 2x^4\)

OpenStudy (anonymous):

wouldnt u add the X to the 2X

OpenStudy (sleepyjess):

No because we are multiplying not adding.

OpenStudy (sleepyjess):

And 2*1 equals 2

OpenStudy (anonymous):

okay

OpenStudy (sleepyjess):

Now, the inside terms are \(\sf 10\) and \(\sf 5\).

OpenStudy (anonymous):

15

OpenStudy (sleepyjess):

Remember, we are multiplying

OpenStudy (anonymous):

50

OpenStudy (sleepyjess):

Yep, the last terms are \(\sf 10\) and \(\sf x^2\) so what does that equal multiplied?

OpenStudy (anonymous):

10x^2

OpenStudy (sleepyjess):

Yep so all together we have \(\sf 10x^2-2x^4+50-10x^2\). The \(\sf 2x^4\) and \(\sf 10x^2\) are negative because in the binomial \(\sf x^2\) is negative.

OpenStudy (sleepyjess):

Now put those in order from the term with the greatest exponent to the term with the lowest exponent.

OpenStudy (anonymous):

10x^2-2x^4-10x^2+50 ?

OpenStudy (sleepyjess):

\(\sf -2x^4\) would be first. What is \(\sf +10x^2-10x^2\)?

OpenStudy (anonymous):

0

OpenStudy (sleepyjess):

Yep so the final equation will be \(\sf -2x^4+50\)

OpenStudy (anonymous):

48x^4

OpenStudy (sleepyjess):

You can't simplify it any further than \(\sf -2x^4 - 50\)

OpenStudy (sleepyjess):

*+50

OpenStudy (anonymous):

thts the answer?

OpenStudy (sleepyjess):

Yes \(\sf -2x^4+50\)

OpenStudy (anonymous):

thanks for the help

OpenStudy (sleepyjess):

\(\LARGE\cal\color{cyan}{No~Problem!}\\\bbox [10pt, magenta,border:5pt solid blue ]{\color{#00ffab}{\huge\cal ~\heartsuit sleepyjess\heartsuit}}\)

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