## Elementary Geometry for College Students (5th Edition)

$-x + 3y = -40$ $y = \frac{x}{3} - \frac{40}{3}$
$-6x + 18y = -240$ 6, 18 and 240 are multiples of 6, and therefore can divide the whole equation by 6. $-x + 3y = -40$ $3y = x - 40$ $y = \frac{x}{3} - \frac{40}{3}$