V/LW=H , you have to isolate the h so you must divide both sides by LW
each book would be 1.9 pounch each because 9.5 divided by 5 is 1.9. to check this do 1.9 times 5 and see if u get 9.5
The slope will be -1/2. If you put it into slope intercept form of y=mx+b, mx will always be the slope.