Question

7(m+5) = 21 What is it?

Answer 1

We want to solve the following expression for m:

`7(m+5)=21`

First, we use the distributive property, and multiply 7 by each term inside the parenthesis:

`\begin{gathered} 7m+7\cdot5=21 \\ \text{as we have }7\cdot5=35\text{ we obtain} \\ 7m+35=21 \end{gathered}`

Now, we substract 35 both sides of the equation:

`\begin{gathered} 7m+35-35=21-35 \\ 7m+0=-14 \\ 7m=-14 \end{gathered}`

And finally, we divide both sides by 7:

`\begin{gathered} (7m)/(7)=(-14)/(7) \\ m=-2 \end{gathered}`

This means that the value of m is -2.