1. ## Factoring Special Products.

These are start to get way to hard now.

Need help on these.

I need help with these, I'm a Senior who is failing in Math. I wanna Grad on time.

2. Originally Posted by Kenlen83
These are start to get way to hard now.

Need help on these.

I need help with these, I'm a Senior who is failing in Math. I wanna Grad on time.
Remember this formula

$\displaystyle (ax)^ 3 + (by)^3 = (ax+by)\times((ax)^2 + (by)^2 - axby)$

Example ;

x^3 + 1/8

= (x)^3 + (1/2)^3 = (x+1/2)(x^2 +1/4 -x/2)

27 x^3 + 1

= (3x)^3 + (1)^3 = (3x+1)(9x^2 + 1 - 3x)

3. These are all sums or differences of cubes:

. . . . .$\displaystyle x^3\, +\, \frac{1}{8}\, =\, (x)^3\, +\, \left(\frac{1}{2}\right)^3$

. . . . .$\displaystyle a^{3y}\, +\, 1\, =\, \left(a^y\right)^3\, +\, (1)^3$

. . . . .$\displaystyle \frac{1}{8}x^3\, -\, \frac{1}{27}y^3\, =\, \left(\frac{1}{2}x\right)^3\, -\, \left(\frac{1}{3}y\right)^3$

To learn how to do the factorizations, try studying a lesson on special factoring formulas.

Then memorize the two "cubes" formulas!!

4. Hey, Thanks... Does that work with both? Can you give me a Example how Number 7 work with that?

5. Originally Posted by Kenlen83
Hey, Thanks... Does that work with both? Can you give me a Example how Number 7 work with that?
Hi Kenlen83,

$\displaystyle a^{3y}+1=(a^y)^3+1^3=(a^y+1)(a^{2y}-a^y+1)$

6. Big Thanks for this.

Thanks everyone, best math site i been on.