Evaluate u+xy where U=3 X=4 Y=7

What are two different ways you could find the value of a? explain these methods.

Nitrogen (n2) undergoes an internally reversible process from 6 bar, 247°c during which pν1.2 = constant. the initial volume is 0.1 m3 and the work for the process is 121.14 kj. assuming ideal gas behavior, and neglecting kinetic and potential energy effects, determine heat transfer, in kj, and the entropy change, in kj/s. show the process on a t-s diagram.

What kind of simple machine is a catapult?