how do you solve this?
2007-07-12 02:47:01 · 9 answers · asked by gfgfd g 1 in Science & Mathematics ➔ Mathematics
You know that a = b - 1, so you can plug in b - 1 for any a in the equation (a-b)^3 - (b-a)^3:
(a - b)^3 - (b - a)^3
=[(b - 1) - b]^3 - [b - (b - 1)]^3
=(b - 1 - b)^3 - (b - b + 1)^3
=(-1)^3 - (1)^3
=(-1) - (1)
=-2
2007-07-12 02:56:05 · answer #1 · answered by Anonymous · 0⤊ 0⤋
a=b-1
(a-b)^3 - (b-a)^3
=[(b-1)-b)^3 - [b-(b-1)]^3
=( -1)^3 - 1^3
= -1-1
= -2
2007-07-12 03:17:33 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Just substitute for b: b = a+1, so
(a-b)^3 - (b-a)^3 = (a - (a+1))^3 - ((a+1) - a)^3 = (-1)^3 - (1)^3 = -2
2007-07-12 02:51:15 · answer #3 · answered by dansinger61 6 · 0⤊ 0⤋
(a - b)^3 - (b -a)^3
Substitute a with b - 1:
(b - 1 - b)^3 - (b - [b - 1])^3
- 1^3 - (b - b + 1)^3
- 1^3 - 1^3
- 1 - 1
- 2
2007-07-15 06:57:35 · answer #4 · answered by Jun Agruda 7 · 2⤊ 0⤋
I follow the same figuring as the others, except with one difference.
(a-b)^3 - (b-a)^3
=((b-1)-b) - (b-(b-1))
=(-1) - (-1)
= 0
The double negative is a positive.
The 'double' minus, ends up adding the last '1' to the first.
2007-07-12 02:57:18 · answer #5 · answered by Marvinator 7 · 0⤊ 1⤋
if a=b-1, then you can rearrange the variables to get the following....
a-b = -1
b-a = 1
thus,
(a-b)^3 - (b-a)^3
= (-1)^3 - (1)^3
= -1 - 1
= -2
2007-07-12 02:50:30 · answer #6 · answered by A C 2 · 1⤊ 0⤋
(b-1-b)^3 - (b - b -1)^3 =
(-1)^3 - (-1)^3 =
whatever you get
2007-07-12 02:52:01 · answer #7 · answered by BWes 3 · 0⤊ 0⤋
substitute (a+1) whereve ryou see b and then expand....
which gives
(-1)^3-(1)^3=-2
2007-07-12 02:50:30 · answer #8 · answered by Anonymous · 0⤊ 0⤋
-2
2007-07-12 02:51:00 · answer #9 · answered by Chuck Schwarzenegger 2 · 0⤊ 0⤋