Question

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

Answer 1

From the question, we have

`\begin{gathered} (a)/(4)=(b)/(7) \\ cross\text{ multiply we have } \\ a*7=4* b \\ 7a=4b \\ a=(4b)/(7) \end{gathered}`

we want to find the value of

`\begin{gathered} (a-b)/(b) \\ We\text{ will substitute a for }(4b)/(7) \end{gathered}`

We have

`\begin{gathered} (a-b)/(b) \\ ((4b)/(7)-b)/(b) \\ ((4b-7b)/(7))/(b) \\ ((-3b)/(7))/(b) \\ =(-3b)/(7)/(b)/(1) \\ =-(3b)/(7)*(1)/(b) \end{gathered}`

b cancels b,

we have our answer as

`=(-3)/(7)`