Question

срочно решите пожалуйста​

Answer 1

$\displaystyle\bf\\\frac{7}{5b+5} -\frac{3}{10b+10} =\frac{7}{5(b+1)} -\frac{3}{10(b+1)}=\frac{7\cdot 2-3}{10(b+1)} =\\\\\\=\frac{14-3}{10(b+1)} =\frac{11}{10b+10}$