I need some serious help on this math plz help much appreciated..will mark brain..

Find the equation of the line with slope =8 and passing through (6,53) write your equation in the form y=mx+b

Donald has x twenty-dollar bills and 11 ten-dollar bill. how much money does donald have? write your answer as an expression.

Sally deposited money into a savings account paying 4% simple interest per year.the first year,she earn $75 in interest.how much interest will she earn during the following year?