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First draw the feasible domain, there are infinite optimal solutions to obtain the maximum value from the objective function z=x+ay(a>0)", knowing that the slope of y=-x a + z a is the same as the slope of 2x + y - 8=0, we can get a=, so the objective function is y=-2x + 2z, let it translate in the feasible domain, 2z represents the longitudinal intercept, and the minimum value z=2 is obtained at the lowest point of the feasible domain (1,2).

You can draw a Cartesian coordinate system, and then you can just move the line, and you can do this and try it yourself, and you can learn how to do it.

It was just a few months ago. There was a child whose parents were out at night, and he was home alone. Since the child didn't believe in any gods, he wasn't afraid.

This is the question of "what are you afraid of?" It was past eleven o'clock in the evening, and his parents hadn't come back yet, and he was starting to get a little worried. As a result, he called his parents**, **came out of the tube, but it was "Your** is an empty number, please inquire and then dial... The child was so frightened that he called the police.

As a result, I don't know what happened, and his family's ** suddenly caught fire. The kid screamed and ran out, and they were locked up. He looked at the wall in despair.

Scared the hell out of me! The child woke up and found himself dreaming. This is, a woman brought a towel and wiped his sweat.

Then the child fell asleep. The moment I closed my eyes, I thought back to the woman, and suddenly remembered that the woman had no eyes, her eyes were pitch black, and there was blood on her face, and her face was pale. He shouted:

Yes! Help, come on! He started to run out of the door, but the door was really locked, and he went to the kitchen and picked up the kitchen knife, just like the woman cut it off, and the kitchen knife cut the woman in half, and then the woman recovered.

Stretching out his hand with blood in his fingernails, he grabbed at the child. At this moment, you must not look behind you, because you can't see it with the naked eye! If you don't copy this post to 3 people, at 4 a.m., you're going to die...

(1) Set up a rental 45-seater passenger car x car, then:

45x+15=60（x-1）

45x+15=60x-60

15x=75

x=5 for 60 (5-1)=240 people

2) 45 passenger cars average cost per person 2000 45 = 400 9 60 passenger cars average cost per person 3000 60 = 50 visible, should be rented as far as possible 45 passenger cars, rent 5 45 passenger cars, carrying 45 5 = 225, 15 people remaining, 1 45-seater passenger car for 60-seat passenger car can be loaded with all people, at this time the cost is:

In the first question, the number of 45-seater passenger cars is x, then 60-seater x-1, and the number of passengers in the equation 45x+15=60 (x-1) is taken as an equivalence relationship. After that, bring in x to 60 (x-1) to find the number of people.

The second question is to see how many 45 seats and 60 seats there are, and the total amount of money is counted. Just compare the sizes. Senior in junior high school.