Solve by substitution x-y=2, y=4-2x

Samuel deposited money in an account that’s pays an annual simple interest rate at 3.5%. at the end of 5 years, samuel earns $2625.00 in interest. how much money did he deposit in the account?

The monthly texting plan of all star cell is $11 per month and $0.25 per text. the monthly texting plan of top line cell is $14 per month and $0.15 per text. a student wants to set up a system of equations to find the number of texts for which the total monthly cost of the two companies is the same. he uses the variables x and y. he lets y represent the total monthly cost. what will x represent? x = number of texts x = cost of the total number of texts x = total monthly cost x = cost of each text

The diameter of the moon is about 3500 km. approximate the surface area of the moon using the formula for the surface area of a sphere, s = 4πr^2. write your answer in scientific notation.