if r*s = rs + s + r then for what value of s is r*s equal to r for all values of r?
(A) -1
(B) 0
(C) 1
(D) 1 / r+1
(E) r
(A) -1
(B) 0
(C) 1
(D) 1 / r+1
(E) r
if we take r as -1 we can wrte this equation as r*s=-1*s+s+r
r*s=r
