### Home > GB8I > Chapter 4 Unit 5 > Lesson INT1: 4.2.2 > Problem4-76

4-76.

For each of the following area models, determine the dimensions (length and width) and write the area as a product and as a sum.

1.  Generic rectangle top edge left blank top edge right $-4$ left edge$3y$ interior left$3y^2$ interior right blank
• Find the length and width of each small rectangle.

 Generic rectangle top edge left$y$ top edge right $-4$ left edge$3y$ interior left$3y^2$ interior right$-12y$

$3y(y−4)=3y^2−12y$

1.  Generic rectangle top edge left $y$ top edge right blank left edge top$3y$ interior left top blank interior top right$-12y$ left edge bottom blank interior left bottom$5y$ interior right bottom blank

Follow the steps in part (a).

 Generic rectangle top edge left$y$$y$ top edge right $-4$ left edge top$3y$ interior left top$3y^2$ interior top right$-12y$ left edge bottom$5$ interior left bottom$5y$ interior right bottom$-20$

$(3y+5)(y−4)=3y^2−7y−20$