## Elementary Technical Mathematics

$-3x+9y=20$ $-3x+9y+3x=20+3x$ $9y\div9=(3x+20)\div9$ $y=\frac{3}{9}x+\frac{20}{9}$ $y=\underset\uparrow{\frac{1}{3}}x+\frac{20}{9}$ $\ \ \ \ \ \$slope $3y=x$ $3y\div3=x\div3$ $y=\underset\uparrow{\frac{1}{3}}x$ $\ \ \ \ \ \$slope The slope is $\frac{1}{3}$ for both equations so the lines are parallel.