xwintersnight
New member
- Joined
- Nov 12, 2007
- Messages
- 18
How exactly would I tackle a problem like 12x[sup:3bag30uz]2[/sup:3bag30uz] - 3?
o_O said:These kind of questions usually tell you that it's a difference of squares problem:
\(\displaystyle a^{2} - b^{2} = (a-b)(a+b)\)
First factor out a 3 so that it'll be easier to deal with: \(\displaystyle 3(4x^{2} - 1)\).
So using our difference of squares formula, you get \(\displaystyle a^{2} = 4x^{2}\) and \(\displaystyle b^{2} = 1\). What's a and b? Once you find that, just plug it back into the formula I gave you (a+b)(a-b)
o_O said:b = 1 is correct. No need for the \(\displaystyle \pm\) since it's compensated by the two binomial expressions. As for a = 4x, not quite. When you square it, you get a[sup:1swrsnb0]2[/sup:1swrsnb0] = 16x[sup:1swrsnb0]2[/sup:1swrsnb0] which isn't what you started with. Keep trying ... a[sup:1swrsnb0]2[/sup:1swrsnb0] = 4x[sup:1swrsnb0]2[/sup:1swrsnb0] ...
xwintersnight said:o_O said:These kind of questions usually tell you that it's a difference of squares problem:
\(\displaystyle a^{2} - b^{2} = (a-b)(a+b)\)
First factor out a 3 so that it'll be easier to deal with: \(\displaystyle 3(4x^{2} - 1)\).
So using our difference of squares formula, you get \(\displaystyle a^{2} = 4x^{2}\) and \(\displaystyle b^{2} = 1\). What's a and b? Once you find that, just plug it back into the formula I gave you (a+b)(a-b)
So, would it end up being 3(2x+1)(2x-1)?
o_O said:Right :wink:
What are you confused about now?