27a^3-8b^3
Can you help me factor this?
Thank you =)
2007-03-29 18:33:25 · 5 answers · asked by scootnoodles 2 in Science & Mathematics ➔ Mathematics
Generally, when you factor something of the form:
x^3 - y^3 = (x - y) (x^2 + xy + y^2)
So... in this case, since 27a^3 = x^3, x = 3a
Likewise, because 8b^3 = y^3, y = 2b
Now...
27a^3-8b^3 = (3a - 2b) [ (3a)^2 + (3a)(2b) + (2b)^2]
So...
27a^3-8b^3 = (3a - 2b) (9a^2 + 6ab + 4b^2)
2007-03-29 18:40:32 · answer #1 · answered by Anonymous · 0⤊ 0⤋
27a^3 = (3a)^3 and 8b^3= (2b)^3
a^3 -b^3 = (a-b) (a^2 -ab +b^2)
27a^3-8b^3 = (3a-2b) (9a^2 -6ab +4b^2)
2007-03-30 01:41:36 · answer #2 · answered by maussy 7 · 0⤊ 0⤋
27a^3 - 8b^3 = (3a)^3 - (2b)^3
= (3a - 2b)[(3a)^2 + (3a*2b) + (2b)^2]
2007-03-30 01:41:33 · answer #3 · answered by M T 2 · 0⤊ 0⤋
(3a-2b)(9a^2+6ab+4b^2)
2007-03-30 01:39:44 · answer #4 · answered by hyungbinkim 3 · 0⤊ 0⤋
that is factored
2007-03-30 01:36:26 · answer #5 · answered by John W 1 · 0⤊ 2⤋