Miguel started a savings account with $150. After 4 weeks, he had $450 dollars, and after 9 weeks, he had $825. What is the rate of change of money (in dollars) in his savings account per week? (Do not include the units when you type your answer.)

Based on what i know about mean, this doesn't add up.

/is used for a fraction 1) if x = 2/3 and y = 3/4, what is the value of (x + y) (x/y) expressed as a common fraction? 2) what is the least positive integer greater than 1 that leaves a remainder of 1 when divided by each of 2, 3, 4, 5, 6, 7, 8, and 9? 3) the ponde family's powerjet pumps 420 gallons of water per hour. at this rate, how many gallons of water will it pump in 45 minutes? 4) kim's insurance company pays 80% of the cost of all prescription medication she purchases in a year beyond the first $250 worth of prescriptions. her prescriptions for this year cost a total of $570. how many dollars of this amounts will kim's insurance company pay?

Solve this equation using substitution. {4x + y = −2} {4x + 6y = 44}