Chapter 1 - Tools of Geometry - 1-8 Perimeter, Circumference, and Area - Practice and Problem-Solving Exercises - Page 67: 59

$A=10x^2+3.5xy-3y^2\ units^2$

Use the formula for the area of a triangle $A=\frac{1}{2}bh$ $A=\frac{1}{2}(5x-2y)(4x+3y)$ Use the FOIL method to multiply the binomials: $A=\frac{1}{2}(20x^2+15xy-8xy-6y^2)$ $A=\frac{1}{2}(20x^2+7xy-6y^2)$ Use the distributive property: $A=10x^2+3.5xy-3y^2$