On subtracting (12a - 9ab - 5b - 2) from the sum of (4a - 7ab - 4b - 5) and (a + 3)(b - 4), we get:

Solve this: (12)2 - (4.5)2(12)2 + 12 × 4.5 + (4.5)2

If x = 4, what is the value of 2x + 3?

If A ⇌ B = A3 + B3 - 3AB, then find the value of 2 ⇌ 1.