Prove that the function y = x & # / x-3, (1 ≤ x ≤ 2) is a decreasing function rt

Prove that the function y = x & # / x-3, (1 ≤ x ≤ 2) is a decreasing function rt

Let: 1 ≤ x1 ≤ x2 ≤ 2 get: F (x1) - f (x2) = X1 ^ 2 / (x1-3) - x2 ^ 2 / (x2-3) = [X1 ^ 2 (x2-3) - x2 ^ 2 (x1-3)] / (x1-3) (x2-3) = [x1x2 (x1-x2) - 3 (x1 + 2) (x1-x2)] / (x1-3) (x2-3) = (x1-x2) (x1x2-3) / (x1-3) (x2-3)