What is the slope of (-2,4) and (3,-4)

Carrie and krystal are taking a road trip from greenville each person has her own map carry in north valley or each person has her own map in the scales on the maps are different and carries map read about in northville are 4.5inches apart the scale on a map is 1 inch equals 20 miles how far is greenville from north valley

Answer this 30 points and brainliest!

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.