Question

Expand (x + y)6.
A. x6 - 6x5y + 15x4y2 - 20x3y3 + 15x2y4 - 6xy5 + y6
B. x6 + 6x5y + 15x4y2 + 20x3y3 + 15x2y4 + 6xy5 + y6
C. x6 - 6x5y - 15x4y2 - 30x3y3 - 15x2y4 - 6xy5 - y6
D. x6 + 6x5y + 15x4y2 + 30x3y3 + 15x2y4 + 6xy5 + y6
I'm pretty sure it's C am I right?

Answer 1

No, it's not C. Notice how there isn't a negative anywhere to be found in the original expression.

Answer 2

Well, without going through the whole cumbersome multiplication, I can tell you that it cannot be A or C because there are no negative numbers in this multiplication.