Factor x
3 - 27y
9Note the following cube root calculations
The cube root of the first term x
3 =
x ← This is {a}
The cube root of the second term 27y
9 =
3y3 ← This is {b}
Since both cube roots are integer constants and powers, x
3 - 27y
9 is in the
Difference of cubes format
The formula for factoring the Difference of cubes is as follows:
a
3 - b
3 = (
a -
b)(
a2 +
ab +
b2)
Calculate ab
ab = (
x)(
3y3)
ab = (
1 x
3)xy
3ab = 3xy
3Calculate the square of the a term:
The square of the a term = (
x)
2 = x
(1 x 2)The square of the a term = (
x)
2 = x
2Calculate the square of the b term:
The square of the b term = (
3y3)
2 = 3
2y
(3 x 2)The square of the b term = (
3y3)
2 = 9y
6Our factored expression using the Difference of cubes formula becomes:
(x - 3y3)(x2 + 3xy3 + 9y6)
Our factored out term becomes:
(x - 3y3)(x2 + 3xy3 + 9y6)