What is this plz come here to help me?

Abbey purchased a house using a fixed rate mortgage. the annual interest rate is 4.2% compounded monthly for 20 years. the mortgage amount is $235,000. what is the monthly payment on the mortgage? this isn't a multiple choice question have to show my work

You can find the constant of proportionality by finding the ratio of

Marco has $38.43 dollars in his checking account. his checking account is linked to his amazon music account so he can buy music. the songs he purchases cost $1.29. part 1: write an expression to describe the amount of money in his checking account in relationship to the number of songs he purchases. part 2: describe what the variable represents in this situation.