To solve for m we want to get m by itself on one side of the equals sign, with everything else on the other side. First we subtract b from both sides, to get it out of the right side of the equation: y - b = mx + b - b y - b = mx Now we divide both sides by x, to get m completely by itself: (y-b)/x = (mx)/x (y-b)/x = m So m is equal to (y-b)/x.
All you need to do is 4,302 divided by 3. You would get 1434 pounds. I did this in my head. You can split it to get 4,200 divided by 3 + 102 divided by 3. You get 1400 + 34 which is 1434.