2) The Sirius-Y54 uses a nuclear reactor as its energy source. If No is the initial mass of the fuelrods before take-off and N is the mass of the fuel rods remaining, and if:​

Which equation can be used to solve for the unknown number? seven less than a number is thirteen. n-7=13 7-n=13 n+7=13 n+13=7

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?

Can someone me with this problem i don't understand i need