Ax + b = 0 solve for 0 Are you able to solve for 0 and If so what is the answer? Please help, I will mark you brainlist :)

Answer this question! 30 points and brainliest! only if you know the answer.

An advertising firm has an old computer that can prepare a whole mailing in 6 hours. with the of newer model the job is complete in 2 hours. how long would it take the newer model to do the job alone?

Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. what distance from city a is the point where the truck and the car will meet?