here's the problem, i'm oblivious to as to what conditions ii, iii, iv, mean, i have never seen that notation and its not *in my notes nor my book. Can someone help me out? Also for problem b) can someone point me in the right direction. Cheers *edit so far for b) i has b) a•w = 4a - 1b - 3c , b•w = 1a + ab + 2c ==> w•(a+b) = w•a + w•b = a - c a = c + 1 by substituting the above into b•w i got b = 3 + c ... are thar any sites that will teach this to me? i dunno what i'm doing.