Question

SOS!! HELP!! Помогите пожалуйста

Answer 1

$= frac{ a^{2} -9 b^{2} }{3ab} : frac{a-3b}{3ab} = frac{(a+3b)(a-3b)}{3ab} * frac{3ab}{a-3b} =a+3b$
$8 frac{4}{7} +3*4 frac{1}{7} =8 frac{4}{7}+12 frac{3}{7} =21$

Answer 2

$frac{a^{2}-9b^{2}}{3ab}:( frac{1}{3b}- frac{1}{a}) = frac{a^{2}-9b^{2}}{3ab}: frac{a-3b}{3ab} = frac{a^{2}-9b^{2}}{3ab} * frac{3ab}{a-3b} = frac{(a-3b)(a+3b)}{3ab}* frac{3ab}{a-3b} \ =a+3b= frac{60}{7}+3* frac{29}{7}= frac{60}{7}+ frac{87}{7}= frac{147}{7}= 21$