17 less the sum of 2 times a number plus another number

Turner's mom measured his room to see how long the wallpaper border needed to be. if two walls are 15 feet long and two walls are 12 feet long, how long should the strip of border be cut?

If 1/√5+1/√5+1=p+q√r , find the values of p, q and r

We just started the introduction into circles and i have no idea how to do this.