r=[(-1)(A/1)]-t+P > explanation > P=(A/1)+rt > subtract "r" from both sides to
get > P-r=(A/1)+t > then subtract "P" from both sides to get > -r=(A/1)+t-P >
then multiply the whole equation by "-1" to make "r" positive > (-1){-r=(A/1)+t-P}
> r=[(-1)(A/1)]-t+P .................. if this was not the answer then I'm sorry ... <3
