Help in understanding a solution of a problem

Hello

I have a receiver design problem and its solution

but I can't understand it

anyone can help me with it ?

A is just a the cascade noise figure equation re-arranged to solve for the third stage noise figure and gain. You are given the realtionship between gain and noise figure.

B is the formula for two tone third order inctercept point re-arragned to solve for third order product power

C is third order intercept point formula re-arranged to solve for the third order product equal to the noise floor of the receiver.

If u need any furthur clarifications, Have a look at Microwave Engineering by Pozar Text book 10th chapter. Very neatly explained in it..!