To simplify the expression \((7n)(6n)\), you can follow these steps:
- Multiply the coefficients (the numbers in front) together: \(7 \times 6 = 42\).
- Multiply the variable \(n\) by itself: \(n \times n = n^2\).
Putting it all together, you get:
\[ (7n)(6n) = 42n^2 \]
So, the simplified expression is:
\[ 42n^2 \]