geometry

The line that passes through (0,5) and (-4,8) has the slope (y_2-y₁)/(x_2-x₁) = (8-5)/(-4-0) = 3/-4 = -3/4

y = mx + b, plug in the point (1,2):

2 = (-3/4)(1) + b

2 = -3/4 + b

b = 2.75

y = (-3/4)x + 2.75

The slope of the line passing through  (0, 5)  and (-4, 8) is given by

[ 8 -  5 ] / [ -4 - 0 ]  =   3/-4  = -3/4

A line parallel to this has the same slope so we have

y = (-3/4) ( x - 1) + 2       simplify

y = (-3/4)x + 3/4 + 2

y = (-3/4)x + 3/4 + 8/4

y = (-3/4)x + 11/4