(1) A and b
a x 16-x
b 15-x x-3
y = 500 x+400( 16-x)+300( 15-x)+600(x-3)
= 500 x+6400-400 x+4500-300 x+600 x- 1800
= 400 x+9 100(3 & lt； = x & lt= 15)
(2) when x=3
The lowest freight is
Y(min)=400*3+9 100
= 10300
1. What are the five subjects in the special edition exam?
There are five courses, namely three public courses and two professional courses. Profession