Chapter 8, Problem 25SGR

To determine

To calculate the area of the rectangle.

Answer to Problem 25SGR

  $3(x^3+x^2-7x)$

Explanation of Solution

Given:

  

Formula used:

Area of the rectangle $=l\times b$

Calculation:

From the given figure,

  $\text{Length of the rectangle}=x^2+x-7$

  $\text{Breadth of the rectangle}=3x$

Substituting in the area of the rectangle,

Area of the rectangle $=l\times b$

  $\begin{array}{c}\Rightarrow (x^2+x-7)\times (3x)\\ \Rightarrow 3x\times x^2+3x\times x-3x\times 7\\ \Rightarrow 3x^3+3x^2-21x\\ \Rightarrow 3(x^3+x^2-7x)\end{array}$

Conclusion:

Thus, the area of the rectangle is $3(x^3+x^2-7x).$