it all seemed pretty easy to start off with i've got all my results. Voltage against current with a variable thing. but i can't do the equation, i have drawen up the graphs and followed the formulas but the results all come out wrong. formulas: m=y/x m=volt/amp r=1/m which is the resistance resistivity= r=p*a/l p=r*l/a After competing these formulas the result comes out wrong HELP