### Home > AC > Chapter 9 > Lesson 9.1.2 > Problem9-20

9-20.

Use a generic rectangle to multiply $\left(x + 2\right)\left(3x − 5\right)$.

Multiply each column value by each row value to fill the rectangle.

$= 3x² + x − 10$

1. What is $\left(3x^{2} + x − 10\right) + \left(x + 2\right)$? How do you know?

$3x² + x−10$ is the same as $\left(x + 2\right)\left(3x − 5\right)$.

The product divided by one factor is the other factor.

$3x − 5$

2. Likewise, determine $\left(3x^{2} + x − 10\right) + \left(3x − 5\right)$.

• See part (a).