1) a^2=b^2 is NOT SUFFICIENT, plausible set of numbers that satisfy this condition is {-1,1,-2,2,-3,3....so on} 2) a=1, gives no info. whatsoever on the value of b so, NOT SUFFICIENT COMBINING BOTH OPTIONS, if a=1 , b^2=1 --> b= +/-1 plausible set is {-1,1} of {NO,YES} so NOT SUFFICIENT So, the answ...