## Elementary Technical Mathematics

$x-4y=12$ $x-4y-x=12-x$ $-4y\div-4=(-x+12)\div-4$ $y=\underset\uparrow{\frac{1}{4}}x-3$ $\ \ \ \ \ \$slope $x+4y=16$ $x+4y-x=16-x$ $4y\div4=(-x+16)\div4$ $y=-\underset\uparrow{\frac{1}{4}}x+4$ $\ \ \ \ \ \ \ \$slope The slopes are not equal and are not negative inverse, so are not parallel or perpendicular.