1. Slope 3/4, through (4,-1)
y = 3/4 x + b
-1 = 3/4(4) + b
-1 = 3 + b
-1 - 3 = b
-4 = b
y = 3/4 x - 4
2. Slope = - 1/2, through (3,0)
y = -1/2 x + b
0 = -1/2(3) + b
0 = -1.5 + b
0 + 1.5 = b
1.5 = b
y = -1/2 x + 1.5
