26.(1)S(OABC)=4*8=32,S(ADEF)=2*14=28,32+28=60,直线y=x/3+4与直线x=4交于G(4,16/3),与直线x=6交于H(6,6),与y轴交于I(0,4)S(ODHI)=(1/2)*(4+6)*6=30,∴直线y=5,y=x/3+4都平分两矩形的总面积.(2)P(3,5).①y=3x-4.(本小题由无穷多解).②-1/3<=k<=3.(3)能,见(2)①。①x=15/4,②y=40x-146.