I need to show that (-x)*y=-(x*y) for a ring. unless it's not true.
A ring is a set R and operations +, * such that (R, +) is an Abelian group, * is associative, and a*(b+c)=a*b+a*c and (b+c)*a=b*a+c*a.
The Attempt at a Solution
I don't know what the first step of this proof will be, I'm looking for the *trick*, as it were.