In order to encourage citizens to save water, a city stipulates that the charging standards for tap

1) Mr. Hu used 18 tons of water in April, and the water fee should be paid

18*meta) function relation:

2) y=<10) y=y=3) How many tons did Mr. Hu use in May:

Let's say Mr. Hu uses x tons of water in May.

x 17 = x = x = tons.

Mr. Hu has too much water at home.

Solution: (1) When 0 x 5, y=2x, when x 5, y=5 2+, the functional relationship between y and x:

y=2x(0≤x≤5)y=

2）x=8，y=

Answer: The water company should collect water charges

This is a chemistry question... Isn't this a pit for me...

（1）.[55-10*2-(20-10)*3]/5+10+(20-10)

21(m³)

2) Can you tell me about it?

No, it won't. I didn't understand the title...

(1) yuan);

2）y=0≤x≤10)

10＜x≤20)

x 20) (3) yuan), yuan), 17, his household water must have exceeded 20 tons, and his household water should be a ton, which is derived from the title:

Answer: a=23, A: His family used 23 tons of water in May

The water fee in October is y1 = 15a + (35-15) * 2a = 55a (yuan), and the water fee in November is y2 = 15a + (30-15) * 2a = 45a (yuan), then the sum of the water charges for the two months is y=y1 + y2 = 55a + 45a = 100a = 144, and the solution is a =

The water fee in October is 15a+20*2a=55a

The water fee in November is 15a+15*2a=45a

The total water bill is 55a + 45a = 100a = 144 yuan a = yuan.

Solution: Set water x tons.

12 * = $<.

The user used more than 12 tons of water.

Yes + x - 12) = x = 20

A: 20 tons of water.

12 times equals yuan, minus equals yuan, divided by equals 8 tons, and 8 plus 12 equals 20 tons.

Solution: If X A

The water fee payable is: MX yuan.

If x>a

The water fee payable is: MA+2m(x-a)= 2mx-ma.

This is a piecewise function.

y= mx m<=a

ma+2m(x-a)=2mx-ma m>a