Chapter 8.4, Problem 34PPS

To determine

To find: The product ${\left(2c-9d\right)}^2$

Answer to Problem 34PPS

  $4c^2-36cd+91d^2$

Explanation of Solution

Given:

  ${\left(2c-9d\right)}^2$

Calculation:

The given expression is ${\left(2c-9d\right)}^2$

Apply the formula ${\left(a-b\right)}^2=a^2-2ab+b^2$ and then simplify

  $\begin{array}{l}{\left(2c-9d\right)}^2\\ ={\left(2c\right)}^2-2\cdot 2c\cdot 9d+{\left(9d\right)}^2\\ =4c^2-36cd+91d^2\end{array}$