Question

Are the two lines `15x-3y = 12` and `y = 5x + 7` parallel or perpendicular?

Answer 1

`15x-3y = 12` and be written as
`color(white)("XXXXX")` `y = 5x-4`
which is a line with slope `5`

`y=5x+7`
also has a slope of `5`

Therefore the two lines are parallel.

The above assumes recognition of the slope y-intercept form for a line:
`color(white)("XXXXX")` `y = mx +b` which has a slope of `m` and a y-intercept of `b`.