Beginning Algebra With Applications, Chapter 2, 2.3, Section 2.3, Problem 54

Translate the phrase "four less than the product of seven and the square of a number" into a variable expression.

$
\begin{equation}
\begin{aligned}
& \text{The unknown number: } n && \text{Assign a variable to one of the number quantities}\\
\\
& \text{Square of the numerator: } n^2 && \text{Use the assigned variable to write an expression for any other unknown quantity.}\\
\\
& \text{Product of seven and the square of the number: } 7n^2 && \text{Again, by using the assigned variable to write an expression for any other unknown quantity.}\\
\\
&= 7n^2 - 4 && \text{Use the assigned variable to write the variable expression.}
\end{aligned}
\end{equation}
$