What is the slope of a line perpendicular to y+2=-4(x-3)

James performed an experiment to see how adding different salts to water affects their freezing points. his data is shown below. concentration of salt solution (mol solute/kg water) freezing point for nacl solution freezing point for mgcl2 solution 0 0°c 0°c 2 -2.5°c -2.8°c 4 -6.0°c -7.5°c 6 -11.0°c -15.0°c 8 -16.5°c -35.0°c how are the freezing points related to the concentrations of the salt solutions?