I need help with this question ​

If the slope of one line equals the slope of another line then ? a) the two lines are intersecting lines b) the two lines are perpendicular lines c) the two lines are parallel lines d) the two lines always have very steep slopes

How do you determine whether a relationship represented as as graph is linear or nonlinear

If sin(x) = 0 and cos(x) = 1, what is tan(x)?