Question

Expand (2x-y)^7
The answer I got was:
128x^7-448x^6y+672x^5y^2-560x^4y^3+280x^3y^4-84x^2y^5+14xy^6-y^7
Am I correct?

Answer 1

I put this in my online calulator and that's what I got...it just doesn't look right, but that's what we both got

Answer 2

you could use pascal's triangle and the binomial theorem