lan583 wrote:

if r@s = rs+r+s, then for what value of s is r@sm equal to r for all values of r?

-1

0

1

1/(r+1)

r

Apllying the defined operation we get:

find s such that

rsm+r+sm = r

holds for every r

since we know nothing about the "m" part of it, plugging in 1/-1/won't help 'cause m can still be anything and upset the equality.

only 0 works because them the 1st and 3rd terms are always zero and r=r, hich is always true

Answer 0 (C)

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