(a+b+c)² =49
Again, (a+b+c)² = a² + b² + c² + 2(ab + bc + ac)
Thus, 35 + 2(ab + bc + ac) = 49
Or, (ab + bc + ac) = 7
Again, we know, a³ + b³ + c³ - 3abc = (a+b+c){(a² + b² + c²) - (ab + bc + ac)}
Or, 151 - 3abc = 7(35 - 7)
Or, -3abc = 7×28
Or, abc = 196/(-3)
Or, abc = -15
Hence, Answer is (-15)