Question

If a/4 = b/7, what is the value of a - b/b ?thank you ! :)

Answer 1

SOLUTION

From the question, we have

$\begin{gathered} \frac{a}{4}=\frac{b}{7} \\ cross\text{ multiply we have } \\ a\times7=4\times b \\ 7a=4b \\ a=\frac{4b}{7} \end{gathered}$

we want to find the value of

$\begin{gathered} \frac{a-b}{b} \\ We\text{ will substitute a for }\frac{4b}{7} \end{gathered}$

We have

$\begin{gathered} \frac{a-b}{b} \\ \frac{\frac{4b}{7}-b}{b} \\ \frac{\frac{4b-7b}{7}}{b} \\ \frac{\frac{-3b}{7}}{b} \\ =\frac{-3b}{7}\div\frac{b}{1} \\ =-\frac{3b}{7}\times\frac{1}{b} \end{gathered}$

b cancels b,

we have our answer as

$=\frac{-3}{7}$