Chapter P, Prerequisites - Section P.5 - Algebraic Expressions - P.5 Exercises - Page 36: 90

See the explanation

$A=(x-20)(y-20),$ a. -The width of the lot is $y,$ to get the width of the building envelope, we substract it from the width of the lot. Therefore, by substracting $10ft$ from two sides we get the width of the building envelope $y-20$. -The length of the lot is $x,$ to get the length of the building envelope, we substract it from the length of the lot. Therefore, by substracting $10ft$ from two sides we get the length of the building envelope $x-20$. b.$A=xy-20x-20y+400$ c. $A_1=(100-20)(400-20)=30,400ft^2,$ $A_2=(200-20)(200-20)=32,400ft^2$ Therefore, the second lot has larger building envelope.