I'm a mod I'll delete your id so don't dare to answer

What number must you add to complete the square x^2+12x=16

Which expression is equivalent to 2x^2+2x-4/2x^2-4x+2

Which speed is the fastest (use 1 mile ≈ 1.6 kilometers)? a. 12 miles/hour b. 18 feet/second c. 19 kilometers/hour d. cannot be determined