A math problem in the first year of junior high school, solved.

If the relative velocity is 240+260=500km h, and the relative displacement is 240+260=500m, the time is 500 (500*10 36)=

A: After two seconds two cars left.

After the encounter, the speed and 500 kilometers are traveled, and the total length of the journey is 500 meters, and the time to leave is reached.

500 500000 = hours = seconds.

Solution: Let the purchase price of this water heater be X yuan.

1800-x=25%x

125%x=1800

x=1440

A: The purchase price of this water heater is 1440 yuan.

2000x90%=1800 (yuan).

The purchase price of the water heater is x

25%x+x=1800

x =1440

A: The purchase price of this water heater is 1440 yuan.

Set the purchase price to $x.

then (1+25%)x=2000*90% gives x=1440

Therefore, the purchase price is 1440 yuan.

Set an annual interest rate of x y

x+y=200x+1000y=solve the equation.

It should be 2000 yuan and 1000 yuan!

Pay attention to the personal income tax of 20% in this question

Set the annual interest rate of $1,000 savings at x

1000x+2000(

x = $1,000 per annum.

The annual interest rate for $2,000 savings is:

If each room needs to be painted with an area of x, each master brushes Y square every day, then each apprentice paints Y-30 every day

3y=8x-40

5(y-30)=9x

The solution yields x=50 and y=120

Each room needs to be brushed 50m2

Each master brushes 120m 2 per day

Each apprentice brushes 90m 2 per day

1 master and 2 apprentices can be brushed every day: 120 + 90 * 2 = 300m 236 rooms need to be brushed area: 50 * 36 = 1800m 2 days required: 1800 300 = 6 days.

(·1) Solution: from the meaning of the question.

m+4=1 solution: m=-3

So the value of m is -3

2) Solution=6m+4-12m+3

6m+7 substitutes m=-3 into the original formula.

25 So the value of the algebraic formula sought is 25