Beginning Algebra With Applications, Chapter 2, 2.3, Section 2.3, Problem 96

Translate the phrase "a number plus four added to the difference between three and twice the number" into a variable expression. Then simplify the expression.

$
\begin{equation}
\begin{aligned}
& \text{The unknown number: } n && \text{Assign a variable to one of the number quantities}\\
\\
& \text{Twice the number: } 2n && \text{Use the assigned variable to write an expression for any other unknown quantity.}\\
\\
& \text{The number plus four: } n + 4 \\
\\
& \text{Difference between three and twice the number: } 3 - 2n\\
\\
&= (3-2n) + (n+4) && \text{Use the assigned variable to write the variable expression.}\\
\\
&= 3 - 2n + n + 4 && \text{Combine like terms}\\
\\
&= 7 + n
\end{aligned}
\end{equation}
$