a*b = 3*a - 6*b + 2, find (5*2)*7 First find (5*2) by substituting a=5 and b=2 in a*b = 3*a - 6*b + 2 5*2 = 3*5 - 6*2 + 2 5*2 = 15 - 12 + 2 5*2 = 3 + 2 5*2 = 5 Since 5*2 = 5, (5*2)*7 becomes 5*7 So we find 5*7 by substituting a=5 and b=7 in a*b = 3*a - 6*b + 2 5*7 = 3*5 - 6*7 + 2 5*7 = 15 - 42 + 2 5*7 = -27 + 2 5*7 = -25 Edwin