write the slope intercept form of the equation of the line with the following conditions.

Question

19. passing through (4,-2) and (-8, -5).
21. passing through (-5,9) and parallel to 3x+y=1.
23. passing through (4,1) and perpendicular to 2x-y=8.

Answer 1

19. the slope is (-5+2)/(-8-4) = 1/4
so, the line is
y+2 = 1/4 (x-4)
or
y+5 = 1/4 (x+8)

Now use that same form for the others, remembering that the slopes of parallel lines are equal, and that the slopes of perpendicular lines multiply to -1.