a \(\ast\) b = a + 2b
a \(\ast\) b = a + b - ab
a \(\ast\) b = a2 + b
a \(\ast\) b = \(\frac{a(b + 1)}{2}\)
Correct answer is B
\(a \ast b = a + b - ab\)
\(b \ast a = b + a - ba\)
On the set of integers, the two above are cumulative as multiplication and addition are cumulative on the set of integers.