# Algebra review help

• Jan 14th 2009, 07:15 PM
chitsu
Algebra review help
My teacher assigned review questions for our algebra semester final. I tried really hard to get the answers correct. She said that I missed seven problems. I asked her for the numbers and she gave me the numbers. I still had the work sheet in class so i wrote down all the problems on a piece of paper. Can you guys help me with these questions? I don't know what i did wrong on them and my teacher still has my work.

• Jan 14th 2009, 07:32 PM
Jameson
I'm having trouble following your post. Is that 5 or 6 problems? Pick one, show me how you think it's done and where you get stuck and I'll help.
• Jan 14th 2009, 07:40 PM
chitsu
I'm not sure what to do on this problem and I'm pretty sure this is where i got stuck on it.

http://i39.tinypic.com/2a6qdg2.png

each line separates a question. Thank you if you can help me! :]
• Jan 14th 2009, 07:47 PM
Jameson
Ok you are doing everything right so far. Now what you need to do is something called completing the square. You need to find the constant that will allow you to factor both the x expression and the y expression into the form you need.

Look at $x^2-6x$. The way you find the constant is you make sure that the only coefficient for the x^2 term is 1, which it is. If not, you need to divide the coefficient out. Now take the number in front of your x term, divide by two, and square it. For this problem it is 9. So the trick is now to add 9 and subtract 9 at the same time so we change nothing about the equation.

So $x^2-6x+9-9 = (x-3)^2-9$ Do you see how that works? Now move the -9 to the right hand side and do the same thing for your y terms.