I need help pls pls pls

Express the following as a function of a single angle, cos(60) cos(-20) - sin(60) sin(-20)

Oliver read for 450 minutes this month his goal was to read for 10% more minutes next month if all of her medicine go how many minutes will you read all during the next two months

Graph the line with the given slope m and y-intercept b. m=-3,b=1