Question

Can someone explain to me

Answer 1

Here's an example of a piecewise function that has three parts, where your choice of parts depends upon the input, x.  If you order 57 shirts, you must use the "14x + 20" part of this function, because 57>50.  Subst. 57 for x in "14x+20."  You'll get 14*57 + 20, or $818.

What's the total cost of ordering 17 shirts?  Note that 17 lies in the interval 0≤x<25.  Therefore you use ONLY the "17x+20" part of the function:

17(17)+ 20 = $309.

32 shirts:  32 is in the second interval, so evaluate "15.80x+20."
We get:  15.80(32)+20 = $525.60 (answer)

Answer 2

You plug the x value into whichever function it applies to. X represents the number of shirts ordered. So for example, the first question asks the total cost if you order 57 shirts. Look at the piecewise function. If says is x>50 (or equal), you use the equation 14x + 20. 57 is greater than 50 so plug it into the equation. (14)(57) + 20 = 818. You should be able to do the rest now. If you have any more questions, you can ask.