Thread: Simplifying: difference of two cubes

Originally Posted by Tenskypoo

based on your previous questions, it makes me feel this should be ...is that right?

yup. I've gotten to where it is


(x+27)(x^2 - (x times 27))+ 27^2
__________________________________
x-3

Originally Posted by Tenskypoo

yup. I've gotten to where it is


(x+27)(x^2 - (x times 27))+ 27^2
__________________________________
x-3

nope

ok, so if it is on top. you would write that as and apply the (difference of two cubes) formula:

ah, because 3 x 3 x 3= 27

So if it was, x^4 - 16 it would be x^4 - 2^4 just as an example to see if i understand.

Originally Posted by Tenskypoo

ah, because 3 x 3 x 3= 27

So if it was, x^4 - 16 it would be x^4 - 2^4 just as an example to see if i understand.

ah, yeah, you could write it like that. but the formula i gave does not apply to that expression. but yes, that's the idea

Originally Posted by Jhevon

nope

ok, so if it is on top. you would write that as and apply the (difference of two cubes) formula:

so would it be

x^3 - 3^3 = (x - 3)(x^2 + (x times 3) + 3^2)

Originally Posted by Tenskypoo

so would it be

x^3 - 3^3 = (x - 3)(x^2 + (x times 3) + 3^2)

yes, that's the numerator

i'd put that over x-3, but cancel out the x-3 since it is in both the numer. and denom. therefore leaving me with



i may have done the part wrong, or it isn't simplified enough

Originally Posted by Tenskypoo

i'd put that over x-3, but cancel out the x-3 since it is in both the numer. and denom. therefore leaving me with



i may have done the part wrong, or it isn't simplified enough

that is fine

Originally Posted by Tenskypoo

yup. I've gotten to where it is


(x+27)(x^2 - (x times 27))+ 27^2
__________________________________
x-3

Make sure you learn and memorize the formula for factoring a difference of cubes before the next test!