Here's the question you clicked on:
anthony~
Expand (x - 2y)4. A: x4 + 8x3y + 24x2y2 + 32xy3 + 16y4 B: x4 - 8x3y + 24x2y2 - 32xy3 + 16y4 C: x4 - 8x3y + 24x2y2 - 34xy3 + 16y4 D: x4 - 8x3y + 28x2y2 - 32xy3 + 16y4
aren't they all the same?
i think its x^4 - 8x^3y + 24x^2y^2 - 32xy^3 + 16y^4 (B)
they only differ in sign changes
@amistre64 actually that and the coefficients.
...28 and 34 .... sneaky
the numbers are different too. the numbers, signs and all that. they're not the same. none of them.
1 4 6 4 1 pascal row x x x x 1 power down 1 -2y -2y -2y -2y power up -------------------
x^4 - 8x^3y + 24x^2y^2 - 32xy^3 + 16y^4??
http://www.wolframalpha.com/input/?i=expand+%28x+-+2y%29%5E4 but yeah, B is good