Divide. (x^3 - 3x^2 + 3x + 1) divided by (x - 2)

A solution containing 20% acid is mixed with a solution containing 10% acid to make 200 liters of a solitution containing 12% acid. How much of the 10% solution was used?

Also... would √(t-2)^2 be just t-2 or the absolute value of t-2?

Thanks!