Simplify the expression: [(x 2 - 2x) / (x 2 + 2x)] × [(3x + 6) / (x - 2)]

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.