(Sinx - cosx)^2 + 2 sinx cosx. Use identities to simplify

Question

^{i know the answer but dont understand the process to get there}

Answer 1

(sinx-cosx)²+2sinxcosx

sin²x-2sinxcosx+cos²+2sinxcosx

-2sinxcosx and 2sinxcosx cancel

that leaves sin²x+cos²x which is equal to 1, the answer

 

Answer 2

expand the first part you will get: sin²x-2sinx cosx+cos²x+2sinx cosx

cancel the opposite like terms you get sin²x+cos²x which is equals 1