line a: y = -3x -10, line b: x + y/2 = 8, line c: 4x = -4y/5 - 8/5

Question

which are parallel or perpendicular please explain.

Answer 1

solve b and c for y

y/2 = -x + 8

y = -2x + 16, it has slope -2

4x=-4y/5 -8/5

-4y =20x + 8

y =-5x-2 it has slope -5

line a has slope -3

slopes are the coefficient of the x term, when the linear equation is solved for y

-3, -2 and -5 are the slopes of line a, b and c

they are parallel if the slopes are the same

they are perpendicular if slopes are negative inverses

for a, b and c, the lines are neither parallel nor perpendicular