ПОВТОРЮЄМО АЛГЕБРУ ЗА 8 КЛАС: 7

7. Подайте у вигляді дробу:

1) $\frac{x+2y}{5}$ + $\frac{4x-7y}{5}$ = $\frac{x+2y+4y-7y}{5}$ = $\frac{5x-5y}{5}$ = $\frac{5(x-y)}{5}$ = x – y;

2) $\frac{x-y}{x^2-4}$ – $\frac{y-2}{x^2-4}$ = $\frac{x-y-y+2}{x^2-4}$ = $\frac{x-2y+2}{x^2-4}$ = $\frac{x-2y+2}{x^2-4}$;

3) $\frac{{4-2m}^{\backslash p}}{m}$ – $\frac{{5-2p}^{\backslash m}}{p}$ = $\frac{4p-2\mathrm{mp}-5m+2\mathrm{mp}}{\mathrm{mp}}$ = $\frac{4p-5m}{\mathrm{mp}}$;

4) $\frac{m}{m-4}$ – $\frac{m^2}{m^2-8m+16}$ = $\frac{m^{\backslash m-4}}{m-4}$ – $\frac{m^2}{({m-4)}^2}$ = $\frac{m^2-4m-m^2}{{(m-4)}^2}$ = $\frac{4m}{{(m-4)}^2}$;

5) $\frac{p^2-p}{3\mathrm{py}}$ • $\frac{3p}{p^2-1}$ = $\frac{p(p-1)•3p}{3\mathrm{py}(p-1)(p+1)}$ = $\frac{p}{y(p+1)}$;

6) 10x² : (–$\frac{2x}{m}$) = –$\frac{{10x}^2•m}{5x}$ = –2xm.