As shown in the figure, the inverse proportional function is known? The image passes through point p? (? , 8), straight line? Q(4，？ ).

(1) Find the function expression of the above inverse proportional function and straight line;

(2) Let this line be equal to? Axis? The two axes intersect at point a. Two points, b, the other intersection of the inverse proportional function image is p, connecting OP and OQ, and finding the area of △OPQ.