### Home > CCA > Chapter 3 > Lesson 3.3.2 > Problem3-103

3-103.

Multiply each of the following expressions. Show all of your work.

1. $(x+3)(4x+5)$

Use a generic rectangle to multiply.  Draw a rectangle and divide it into four equal parts.

Put the products on the outside of the rectangle. The left edge top is plus three. The left edge bottom is X. The bottom edge left is four X. The bottom edge right is plus 5.

Use length times width to find the areas of the small rectangles.

Write the total area as a sum.
$4x^2+12x+5x+15$

$4x^2+17x+15$

2. $(−2x^2−4x)(3x+4)$

Follow the steps in part (a).

$−6x^3−20x^2−16x$

3. $(3y−8)(−x+y)$

Follow the steps in part (a).

4. $(y−4)(3x+5y−2)$

Follow the steps in part (a).