Is each line parallel, perpendicular, or neither parallel nor perpendicular to the line - x+4y=20?

y=-4x-3

y=-14x+6

-x+4y=8

4x+y=-1

Find the slopes of each

for

ax+by=c

slope=-a/b

for y=mx+b

m=slope

the slopes of paralell lines are equal

the slopes of perpendicular lines, when multiplied together, yeild - 1

so

-1x+4y=20

sloope = - (-1) / 4=1/4

check each

y=-4x-3

-4 times 1/4=-1

perpendicular

y=-1/4x+6

-1/4 and 1/4

neither

-1x+4y=8

- (-1) / 4=1/4

1/4=1/4

paralell

4x+1y=-1

-4/1=-4

-4 times 1/4=-1

perpendicular

y=-4x-3: perpendicular

y=-14x+6: neither

-x+4y=8: paralell

4x+y=-1: perpendicular