A..Consider an economy of 2 men who consume just 2 goods. Each man starts with a given endowment of goods x and y and each acts as a price-taker, or in other words, accepts prices as given.
Assume the men have the following utility functions:
U1=x1y1
U2=x2x2 y2
Where x1 is the amount of good x consumed by man 1 and y1 is the amount of good y consumed by man 1.
Man 1 has an endowment of 40 units of x

x2x2表示x2的平方，我不知道怎么弄

B. Write the first order equilibrium conditions of exchange. Show that in the absence of trade the condition will not generally be fulfilled, and that there exist some prices at which mutually beneficial trade can take place. Given the commodity endowments indicated, indicate the range of prices consistent with mutually beneficial trade.
完全不会做，谁能给点提示啊？

谢谢大家