Упростите выражение: a) (x+y черта дроби x-y минус x-y черта дроби x+y) разделить xy черта дроби x во второй степени-y

а) ((x + y)/(x – y) – (x – y)/(x + y)) : (x * y)/(x² – y²) = (((x + y) * (x + y))/((x – y) * (x + y)) - ((x - y) * (x - y))/((x + y) * (x - y))) * (x² – y²)/(x * y) = ((x + y)²/(x² – y²) – (x - y)²/(x² – y²)) * (x² – y²)/(x * y) = ((x + y)² - (x - y)²)/(x² – y²) * (x² – y²)/(x * y) = (x² + 2 * x * y + y² - (x² - 2 * x * y + y²))/1 * 1/(x * y) = (x² + 2 * x * y + y² - x² + 2 * x * y - y²)/(x * y) = (4 * x * y)/(x * y) = 4.

б) ((2 * x)/(x – 2) – 1/(x + 2)) : (6 * x² + 9 * x * 6)/(x² - 4) = (2 * x * (x + 2))/((x – 2) * (x + 2)) – (1 * (x – 2))/((x + 2) * (x – 2)) * (x² - 4)/(6 * x² + 9 * x + 6) = ((2 * x² + 4 * x)/(x² - 4) – (x – 2)/(x² - 4)) * (x² - 4)/(3 * (2 * x² + 3 * x + 2)) = (2 * x² + 4 * x – x + 2)/(x² - 4) * (x² - 4)/(3 * (2 * x² + 3 * x + 2)) = (2 * x² + 3 * x + 2)/1 * 1/(3 * (2 * x² + 3 * x + 2)) = 1/1 * 1/(3 * 1) = 1 * 1/3 = 1/3.