Given that * is a binary operation on the set I of integers.

The operation is defined by a*b = 2a + b – 3.

We need to find the value of 3*4.

Since 3 and 4 belongs to the set of integers we can use the binary operation.

⇒ 3*4 = (2×3) + 4–3

⇒ 3*4 = 6 + 1

⇒ 3*4 = 7

∴ the value of 3*4 is 7.