Thursday
May 5, 2016

# Homework Help: Algebra (new one since I put "match" (bad speller)

Posted by Sarah on Sunday, January 21, 2007 at 9:20pm.

I have a few match problems that I can't figure out.
1.solve: 3x+5=x√7 (that's a radical sign)
2.factor: (2k+3)2-(2x+3)(y-2)-20(y-2)2 (the "2" after (2k+3) ans (y-2) is suppose to be a square sign.

thanks if you can help, or even if you can't

For number 2:
First, FOIL out (2k+3)^2. You should get:
4k^2 + 12k + 9.
Then, FOIL out (2x+3)(y-2). You should get:
2xy - 4x + 3y - 6. You wanted to subtract the first part by the second:
4k^2 + 12k + 9 -(2xy - 4x + 3y - 6).
Distribute the negative:
4k^2 + 12k + 9 - 2xy + 4x - 3y + 6.
Combine like-terms:
4k^2 + 12k - 2xy + 4x - 3y + 15.
Before multiplying 20 by (y-2)^2, FOIL out the (y-2)^2. You should get:
y^2 - 4y + 4.
Now multiply by 20:
20y^2 - 80y + 80.
Now, take the equation from 6 lines up and subtract by this part:
4k^2 + 12k - 2xy + 4x - 3y + 15 -(20y^2 - 80y + 80).
Distribute the negative:
4k^2 + 12k - 2xy + 4x - 3y + 15 - 20y^2 + 80y - 80.
Now, combine like-terms to finish:
4k^2 + 12k - 2xy + 4x + 77y - 20y^2 - 65.