Question

75 баллов!!!!!!!!!!Решите плиз!)))))

Answer 1

$1) frac{5b}{14} + frac{9b}{14}=frac{14b}{14}=b \ 2) frac{9m}{7n} - frac{2m}{7n}=frac{7m}{7n}=frac{m}{n} \ 3) frac{5x-3y}{8z} + frac{3x-13y}{8z} =frac{8x-16y}{8z}=frac{8(x-2y)}{8z}=frac{x-2y}{z} \ \ 1) frac{3}{m} + frac{5}{n} =frac{3n+5m}{mn} \ 2) frac{4}{x} - frac{3}{xy} = frac{4y-3}{xy} \ 3) frac{7}{9ab}- frac{13}{12ab}= frac{28-39}{36ab}=-frac{11}{36ab} \ \1)frac{x+4}{2(x-3)}-frac{x+1}{x-3} =frac{x+4-2x-2}{2(x-3)}=frac{2-x}{2(x-3)}$
$2)frac{a+3}{3a-3}+frac{2-a}{5a-5} =frac{a+3}{3(a-1)}+frac{2-a}{5(a-1)}=frac{5(a+3)+3(2-a)}{15(a-1)}=frac{5a+15+6-3a}{15(a-1)}=$$frac{2a+21}{15(a-1)} \ 3) frac{x+5}{x-5} - frac{x-1}{x+5} =frac{(x+5)^2-(x-1)(x-5)}{(x-5)(x+5)} =frac{x^2+10x+25-(x^2-6x+5)}{(x-5)(x+5)} =$$frac{16x+20}{(x-5)(x+5)} =frac{4(4x+5)}{(x-5)(x+5)} \ 4) frac{4b}{3b-21}+ frac{3b}{14-2b} =frac{4b}{3(b-7)}+ frac{3b}{2(7-b)} =frac{4b}{3(b-7)}- frac{3b}{2(b-7)} =frac{8b-9b}{6(b-7)} =$$-frac{b}{6(b-7)}=frac{b}{6(7-b)}$