Question

When fifteen is reduced by one third of a number, the results is 7. The number

Answer 1

we wirte the expression on numbers

`15-(x)/(3)=7`

where x is the missing number

to solve

subtract 15 on both sides

`\begin{gathered} 15-15-(x)/(3)=7-15 \\ -(x)/(3)=-8 \end{gathered}`

we can remove negative sign on both sides

`\begin{gathered} (x)/(3)=8 \\ \end{gathered}`

and solve for x multipliying 3 on both sides

`\begin{gathered} 3*(x)/(3)=8*3 \\ \\ x=24 \end{gathered}`

the value of missing number is 24

Other way

`15-(x)/(2)=7`

solve for x moving terms

`\begin{gathered} -(x)/(3)=7-15 \\ \\ -(x)/(3)=-8 \\ \\ x=-8*-3 \\ \\ x=24 \end{gathered}`