Chapter 4 - Section 4.3 - Systems of Linear Equations and Problem Solving - Exercise Set - Page 232: 31

$3000$ units

Given, $C(x) = 1.2x+1500$ $R(x) = 1.7x$ To find break-even point, $C(x) = R(x) $ $1.2x+1500=1.7x$ $1500=1.7x-1.2x$ $1500=0.5x$ $x = \frac{1500}{0.5} = \frac{15000}{5} = 3000$ $3000$ units must be sold to break-even.