X to 4 / 5 = 1 / 3 to 2 / 15

X to 4 / 5 = 1 / 3 to 2 / 15

If you agree with my answer, please accept it in time, ~ your adoption is my driving force ~ ~ ~ if there are any new questions, please don't ask me

2.5 times (3 + x) = 15

2.5 times (3 + x) = 15
3+x=6
x=6-3
x=3

{x/2-y/5=4 x/5-y/15=3
Solving equations by substitution method

x/2-y/5=4
Multiply left and right by 10
5x-2y=40①
x/5-y/15=3
Multiply left and right by 15
3x-y=45②
② Multiply by two
6x-2y=90③
③ - 1
x=50
Substituting in (2)
y=105
To sum up, x = 50, y = 105

If a + 1 / a = 4 (0 < a < 1), find the value of √ a - √ 1 / A. is it √ 2 or - √ 2

－√2

-2X ^ 2 + XY + y ^ 2-6x-y-2 x ^ 2 is the square of X

The original formula = - 2x ^ 2 + (Y-5) x + (y + 1) (Y-2) = - (2x + y + 1) (X-Y + 2)

There are five boxes of fruit, each box weighs 50N. Now we need to move them from the first floor to the third floor. You can move them all at one time, or you can move a box five times at a time. Which way do you think you can do more work on fruit? Which way needs to consume more energy in your body? Please explain why

(1) The total gravity of the fruit is g matter, and the work done on the fruit is: W useful = g matter h. so the work done on the fruit by the two methods is the same; (2) when they are all carried up at one time, w extra 1 = g person h. when they are carried up five times, w extra 2 = 5g person h. from W total = w useful + W extra, we can know that w total 1 < w total 2. Answer: the work done on the fruit by the two methods is the same; each time, a box is carried up five times There's a lot of energy inside

Merge congeners-2a + 3 (1 / 3A + b) - 2 (3a-1 / 2b)

-2a+3(1/3a+b)-2(3a-1/2b)
=-2a+a+3b-6a+b
=(-2+1-6)a+(3+1)b
=-7a+4b

How many kilograms per cubic centimeter is 4.2 kilograms per cubic decimeter?
Such as the title
How to solve the problem

4.2kg/dm^3
=4.2kg/1000cm^3
=0.0042kg/cm^3

The fruit shop brought in a batch of fruits, and sold 60 kg on the first day, which was exactly 23 on the second day. In the two days, 14% of all the fruits were sold. How many kg of these fruits were originally sold?

(60 + 60 △ 23) △ 14 = (60 + 90) × 4 = 150 × 4 = 600 (kg). A: this batch of fruit is 600 kg

If the efficiency increases by 1 / 8 after 3 days' work, how many days will it take to complete 1 / 3 of this batch of parts?

If the total amount of work of this batch of parts is 1, and 1 / 2 can be completed in 128 days according to the plan, it will take 128 * 2 = 256 (days), 1 / 256 every day, 3 * 1 / 256 = 3 / 256 in 3 days, and (1 + 1 / 8) * 1 / 256 = 9 / 2048 every day when the efficiency is improved by 1 / 8