Distribute and Simplify help

• Apr 27th 2009, 04:57 AM
elitescouter
Distribute and Simplify help
Ok I have to Distribute and Simplify...

2x(3x-24) + 4(2x+4+3y) - 2y(2x + 2y) - x(x-y)

Any help, much appriciated.
• Apr 27th 2009, 05:13 AM
stapel
Quote:

Originally Posted by elitescouter
Distribute and Simplify...

2x(3x-24) + 4(2x+4+3y) - 2y(2x + 2y) - x(x-y)

Where are you stuck in this simplification with parentheses exercise? (It's a lot easier for us to "see" where you're having trouble if you show us what you've tried.)

You probably started with something like the following:

. . . . .\$\displaystyle 2x(3x\, -\, 24)\, +\, 4(2x\, +\, 4\, +\, 3y)\, -\, 2y(2x\, +\, 2y)\, -\, x(x\, -\, y)\$

. . . . .\$\displaystyle 2x(3x)\, +\, 2x(-24)\, +\, 4(2x)\, +\, 4(4)\, +\, 4(3y)\, -\, 2y(2x)\, -\, 2y(2y)\, -\, x(x)\, -\, x(-y)\$

. . . . .\$\displaystyle 6x^2\, +\, (-48x)\, +\, 8x\, +\, 16\, +\, 12y\, -\, 4xy\, -\, 4y^2\, -\, x^2\, -\, (-xy)\$

Where did you go from there?

Please be complete. Thank you! (Wink)
• Apr 27th 2009, 05:27 AM
elitescouter
To be honest I have no idea how to do this... That is why I am here. I have done problems like this before but never with x and y's so that is where I got confused.
• Apr 27th 2009, 05:38 AM
mr fantastic
Quote:

Originally Posted by elitescouter
To be honest I have no idea how to do this... That is why I am here. I have done problems like this before but never with x and y's so that is where I got confused.

Quote:

Originally Posted by stapel
[snip]
You probably started with something like the following:

. . . . .\$\displaystyle 2x(3x\, -\, 24)\, +\, 4(2x\, +\, 4\, +\, 3y)\, -\, 2y(2x\, +\, 2y)\, -\, x(x\, -\, y)\$ Line 1

. . . . .\$\displaystyle 2x(3x)\, +\, 2x(-24)\, +\, 4(2x)\, +\, 4(4)\, +\, 4(3y)\, -\, 2y(2x)\, -\, 2y(2y)\, -\, x(x)\, -\, x(-y)\$ Line 2

. . . . .\$\displaystyle 6x^2\, +\, (-48x)\, +\, 8x\, +\, 16\, +\, 12y\, -\, 4xy\, -\, 4y^2\, -\, x^2\, -\, (-xy)\$ Line 3

Where did you go from there?

[snip]

Next line: ....?

You have been given the first three lines of the solution and been asked to try and get the next line. What did you try? Where do you get stuck in going from the third line to the next line?
• Apr 27th 2009, 05:48 AM
elitescouter
This is what i got

\$\displaystyle 5x^2\, -\, 48x\, +\, 16\, +\, 12y\, -\, 3xy\, -\, 4y^2\,\$
• Apr 27th 2009, 05:54 AM
mr fantastic
Quote:

Originally Posted by elitescouter
This is what i got

\$\displaystyle 5x^2\, -\, {\color{red}48} x\, +\, 16\, +\, 12y\, -\, 3xy\, -\, 4y^2\,\$

The number in red is wrong.
• Apr 27th 2009, 06:02 AM
elitescouter
Quote:

Originally Posted by mr fantastic
The number in red is wrong.

\$\displaystyle 5x^2\, -\, -48x\, +\, 16\, +\, 12y\, -\, 3xy\, -\, 4y^2\,\$

Did I forget to make it a negative 48?
• Apr 27th 2009, 06:06 AM
mr fantastic
Quote:

Originally Posted by elitescouter
\$\displaystyle 5x^2\, -\, -48x\, +\, 16\, +\, 12y\, -\, 3xy\, -\, 4y^2\,\$

Did I forget to make it a negative 48?

It's meant to be - 40x.

Go back and look at line 3. There are two x terms. You have not taken into account the second.
• Apr 27th 2009, 06:09 AM
elitescouter
Quote:

Originally Posted by mr fantastic
It's meant to be - 40x.

Go back and look at line 3. There are two x terms. You have not taken into account the second.

Ok, Thank You!!! Wow I need to do more of these excercises I got a exam soon and I don't want to be stuck on something like this.