For each of the following linear equations, answer the questions that follow:
(a) 4x=20
(b) 5y+7=0
(c) x−9=0
(d) 3y=−12
(i) Rewrite every equation in its simplest form.
(ii) Identify whether the line represented by each equation is horizontal or vertical.
(iii) For every horizontal line, state its slope and y-intercept. For every vertical line, state its slope and x-intercept.