Prove that `**: R xx R to R ` defined as `a ** b =a+2ab` is not associative

Explanation

To prove that the operation defined as \( a \ast b = a + 2ab \) is not associative, we need to show that \( (a \ast b) \ast c \neq a \ast (b \ast c) \) for some values of \( a, b, c \).

### Step 1: Calculate \( (a \ast b) \ast c \)

1. Start with the definition of the operation:
\[ a \ast b = a + 2ab \]
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