# How do you solve 7.1= 3.8+ n?

Mar 18, 2018

#### Answer:

$n = 3.3$

#### Explanation:

Given: $7.1 = 3.8 + n$

Don't like decimals so lets get rid of them. Multiply everything on both sides by 10

$71 = 38 + 10 n$

As per convention put the unknown on the left. So turn everything round the other way

$10 n + 38 = 71 \leftarrow \text{ Means exactly the same thing}$

Subtract $\textcolor{red}{38}$ from both sides

$\textcolor{g r e e n}{10 n + 38 = 71 \textcolor{w h i t e}{\text{ddd")->color(white)("ddd")10n+38color(red)(-38)color(white)("d")=color(white)("d}} 71 \textcolor{red}{- 38}}$

$\textcolor{g r e e n}{\textcolor{w h i t e}{\text{ddddddddddddd.d")->color(white)("ddd")10n + color(white)("dd")0color(white)("ddd.")=color(white)("ddd}} 33}$

Divide both sides by $\textcolor{red}{10}$

$\textcolor{g r e e n}{10 n = 33 \textcolor{w h i t e}{\text{ddddddd")->color(white)("ddd")10/color(red)(10)ncolor(white)("d")=color(white)("d}} \frac{33}{\textcolor{red}{10}}}$

But $\frac{10}{10} = 1 \mathmr{and} 1 \times n = n$ giving:

$\textcolor{g r e e n}{n = 3.3}$