Determine which two equations represent parallel lines.?

Question

(a) y = –7x + 4 (b) y = 7x + 4 (c) y = x + 4 (d) y = –7x + 7

Answer 1

Parallel lines have the same gradient, but a different offset.
In: y = mx + c, m is the gradient, c is the offset.

So the lines with y= -7x... are parallel.

Answer 2

(a) and (d) represent parallel lines because using y = mx+b, m is the slope. if you're comparing two equations whether they're parallel or not, the slope has to be the same. in this case, both slopes are -7. (b)'s slope is 7, and c's slope is 1, so there is nothing that has the same slope if you're comparing it to the other three choices.