Please Help I don’t understand

You make and sell triangular flags. each flag has a base of  3.53.5  feet and a height of  2.52.5  feet. fabric for the flags costs  $0.40$0.40  per square foot. what is the cost to make one flag?

How do i do this activity, is appreciated

If you apply the changes below to the linear parent function f(x)=x what is the equation of the new function vertically stretched by a factor of 3 flip over the x axis