two formulas that you need are the formula for slope which is (y2-y1)/(x2-x1) and point slope formula which is (y-y1)=m(x-x1) where m equals your slope.
1) (0+4)/(3+1)= 4/4 which is 1 (when subtracting a negative, you can just add)
(y-0)=1(x-3) y=x-3
2) (-2-4)/(0-1)= -6/-1 which is 6 (negative divided by a negative is a positive)
(y+2)=6(x-0) y+2=6x y=6x-2
