Giải câu 2 trang 54 toán VNEN 8 tập 1.
a) $\frac{5x – 10}{x^{2} + 7}$ : (2x – 4) = $\frac{5(x – 2)}{x^{2} + 7}$. $\frac{1}{2(x – 2)}$ = $\frac{5}{2(x^{2} + 7)}$;
b) (x$^{2}$ - 25) : $\frac{2x + 10}{3x – 7}$ = (x – 5)(x + 5). $\frac{3x – 7}{2(x + 5)}$ = $\frac{(x – 5)(3x – 7)}{2}$;
c) $\frac{x^{2} + x}{5x^{2} – 10x + 5}$ : $\frac{3x + 3}{5x – 5}$ = $\frac{x(x + 1)}{5(x – 1)^{2}}$. $\frac{5(x – 1)}{3(x + 1)}$ = $\frac{x}{3(x – 1)}$.