Chapter 10 - Section 10.3 - Solving Nonlinear Systems of Equations - Exercise Set - Page 625: 50

3,500 frames at a price of 65.50

Supply: $p=9x+34$ Demand: $p=-2x^2+90$ $9x+34=-2x^2+90$ $9x+34+2x^2-90=-2x^2+90+2x^2-90$ $2x^2+9x-56=0$ $(2x-7)(x+8)=0$ $2x-7=0$ $2x-7+7=0+7$ $2x=7$ $2x/2=7/2$ $x=3.5$ $x+8=0$ $x+8-8=0-8$ $x=-8$ We can’t have a negative quantity, so we ignore this answer. $x=3.5$ $p=9x+34$ $p=9*3.5+34$ $p=31.5+34$ $p=65.5$