let m be the slope and b the y-intercept:
m=(y-y)/(x-x) and y=mx+b
Line A
y=4x-3.2
Line B
(3,0) and (0,6)
m= 6/-3= -2
y= -2x+b
0=-2(3)+b
b=6
y= -2x+6
Line C
(1.5,0) and (0,-6)
m=-6/-1.5=4
y=4x+b
0=4(1.5)+b
b = -6
y=4x-6
Line D
(-3,0) and (0,3)
m=3/3=1
y=x+b
0=-3+b
b=3
y=x+3