
<h2>now let's flip this equation to make things easier</h2>

<h2>now move -3 to the other side</h2><h3>when we move -3 to the other side it turns into positive 3</h3>

<h2>now add the values on both sides</h2><h3>n + 2n will be equal to 3n and 9 + 3 will be equal to 12</h3>

<h2>now move 3 to the other side</h2><h3>the multiplication sign that binded 3 and n together will change into division when moved to the other side</h3>

<h2>when we divide 12 and 3 we will get 4</h2>

<h2>so final answer is 4</h2>
<h3>hope that helps !</h3>