Решение
1) 1/(4x² - y²) : (2x + y)/(y - 2x)² = (2x - y)² / [(4x² - y²)*(2x + y)] =
= (2x - y)² / [(2x + y)*(2x - y)*)*(2x + y)] = (2x - y) / (2x + y)²
2) (2x - y) / (2x + y)² - (2x - y)/(4x² + 2xy) = (2x - y) / (2x + y)² -
- (2x - y)/[2x(2x + y)] = [2x(2x - y) - (2x + y)*(2x - y)] / [2x(2x + y)²] =
(4x² - 2xy - 4x² + y²) / [2x(2x + y)²] = - y (2x - y) / [2x(2x + y)²]
3) - y (2x - y) / [2x(2x + y)²] * [(2x + y) / y²] = (y - x) / [2xy(2x + y)]