Which postulate or theorem justifies the following statement? if two angles are a linear pair, then they are supplementary angles

In what form is the following linear equation written y=9x+2

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

Which of the following answers is 5/25 simplified? 1/5 5/5 2/5 1/25