You need to get everything away from the specific variable that you need. In order to do that, you need to do the opposite function. The opposite of addition is subtraction (and vice versa) and the opposite of multiplication is division (and vice versa). Therefore, P=a+b+c turns into P-b-c=a. C=[tex] \pi [/tex]d turns into C/[tex] \pi [/tex]=d. a=F/m turns into am=F. d=mt+b turns into (d-b)/m=t.
