Chapter 1 - Section 1.3 - Algebraic Expressions - 1.3 Exercises - Page 35: 136

a) $b^{2} -(b-2x)^{2}$ b) $4x(b-x)$

a) $A_{1} = b^{2}$ $A_{2} = (b-2x)^{2} $ Therefore, mowed area = $b^{2} -(b-2x)^{2}$ b) $b^{2} - (b-2x)^{2}$ $= [b - (b-2x)][b + (b-2x)]$ $= (b - b + 2x)(b + b - 2x)$ $= (2x)(2b - 2x)$ $= (2x)2(b - x)$ $= 4x(b-x)$