the directions are: factor the following completely over the set of real nmbers
i'm going to write it out partly in words
27b to the 3rd power minus 64
plz show ur work
2007-06-29 08:39:06 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
27b^3 - 64
the expression is a difference of perfect cubes
a^3 - b^3 = (a - b) (a^2 + ab + b^2)
27 = 3^3
64 = 4^3
3^3 b^3 - 4^3
(3b)^3 - 4^3
use the formula above, and you'll get
(3b - 4) (9b^2 + 12b + 16)
2007-06-29 08:42:55 · answer #1 · answered by 7 · 1⤊ 0⤋
This is a diifference of cubes.
(3b-4)(9b^2+12b+16) is the answer and there really isn't any work to be shown. If you can recognize this, it always works like this:
Take the cube root of the first term and the second term. This goes in your first set of (). Then from the first (), square the first term, multiply the 2 terms together, but change the sign, then square the last.
2007-06-29 15:45:32 · answer #2 · answered by Freddie 2 · 1⤊ 0⤋
27b^3-64
= (3b-4)(9b^2 + 12b +16)
2007-06-29 15:47:17 · answer #3 · answered by ironduke8159 7 · 0⤊ 0⤋