Question

ПОМОГИТЕ ВТОРОЙ РАЗ ПИШУ

Answer 1

$left ( frac{15x}{x^2-9} - frac{3}{3-x} right )cdot frac{x^2-9}{2x+1} =left ( frac{15x}{(x-3)(x+3)} + frac{3}{x-3} right )cdot frac{(x-3)(x+3)}{2x+1} =\\= frac{15x+3(x+3)}{(x-3)(x+3)} cdot frac{(x-3)(x+3)}{2x+1} = frac{15x+3x+9}{2x+1} = frac{18x+9}{2x+1} =\\= frac{9(2x+1)}{2x+1} =9$