Verify as an identity: cos(90°+x) = -sinx
i'm not sure how to go about this question

Abank gives 6.5% interest per year. what is the growth factor b in this situation?

The u-drive rent-a-truck company plans to spend $13 million on 320 new vehicles. each commercial van will cost $25 comma 000, each small truck $50 comma 000, and each large truck  $80 comma 000. past experience shows that they need twice as many vans as small trucks. how many of each type of vehicle can they buy?

65% of students in your school participate in at least one after school activity. if there are 980 students in you school, how many do not participate in an after school activity?