Question

A^2-9b^2/3ab :(1/3b -1/a)
A=8 4/7
B= 4 1/7

Answer 1

$frac{a^2-9b^2}{3ab} :(frac{1}{3b} -frac{1}{a})=frac{(a-3b)(a+3b)}{3ab}:frac{a-3b}{3ab}=frac{(a-3b)(a+3b)}{3ab}*frac{3ab}{a-3b}=\=a+3b$
$a=8frac{4}{7}=frac{60}{7}\b=4frac{1}{7}=frac{29}{7}\a+3b=frac{60}{7}+3*frac{29}{7}=frac{147}{7}=21$