Question

Зная что a-b/b=9 найдите 3a+b/a

Answer 1

$\frac{a-5b}{b}=9\; \; \Rightarrow \; \; \frac{a}{b}-\frac{5b}{b}=\frac{a}{b}-5=9\; \; \Rightarrow \; \; \frac{a}{b}=9+5=14\\\\\frac{3a+b}{a}=\frac{3a}{a}+\frac{b}{a}=3+\frac{b}{a}=3+\frac{1}{\frac{a}{b}}=3+\frac{1}{14}=3\frac{1}{14}$

Answer 2

$\frac{a-5b}{b} =9\\ \\ a-5b=9b\\ \\ a=14b\\ \\ \frac{a}{b} =\frac{14b}{b} =14\\ \\ \frac{3a+b}{a} =\frac{3*14b+b}{14b} =\frac{42b+b}{14b} =\frac{43b}{14b} =3\frac{1}{14}$