There is an equation problem in Xiaoming's exercise book. One of the numbers is polluted by ink and becomes (3x + 1) / 5 = 1 - (x +) / 5. The solution of this equation is 1 / 4

There is an equation problem in Xiaoming's exercise book. One of the numbers is polluted by ink and becomes (3x + 1) / 5 = 1 - (x +) / 5. The solution of this equation is 1 / 4

If we take 1 / 4 of the solution of the equation, we get
(3/4+1)/5=1-(1/4+?)/5
3/4+1+1/4+?=5
?=5-2=3

It is known that the solution of the equation 5x-2m = 3x-6m + 1 about X is x, satisfying - 3 < x ≤ 2, and finding the integer value of M

By solving the equation 5x-2m = 3x-6m + 1, x = 12-2m. ∵ - 3 ∵ x ≤ 2, ∵ 12 − 2m ∵ 312 − 2m ≤ 2, the integer value of - 34 ≤ m < 134, ∵ m is 0, 1

It is known that the equation 5x-3 = 2x + 6 and the equation 3x + a minus 1-5x = 1 have the same solution

5x-3＝2x＋6
3x=9
x=3
3x + a minus 1-5x = 1
x=3
So (9 + a) / 12 - (1-15) / 8 = 1
Take 12 on both sides
9+a+21=12
a=-18

It is known that the equation of X; 3 {X - (2x - a third)} = 4x and equation (3x + a of 12) - (1-5x of 8) = 1 have the same solution
Then a is

X=72/7
a=27

What is the least common multiple of 16, 24 and 28?

336

The ratio of [1] x to 14 is equal to the ratio of 2.8 to 0.7, the ratio of x [2] 2.7 to X and the ratio of 0.9 to 0.6 are the same, the ratio of x [2] 2.7 to X is the same

【1】
x:14=2.8:0.7
x:14=4
x=56
【2】
2.7:x=0.9:0.6
x:2.7=2/3
x=1.8

If a and B are rational numbers, a ＜ 0, 0 ＜ B, and | B ＜ a |, then what is the size relationship of a, B, - A, - B?
A.b＜-a＜-b＜a B.a＜-b＜b＜-a C.b＜-a ＜a ＜-b D.-a＜-b＜b＜a

Choose B
A ＜ 0, 0 ＜ B, and | B ＜ a |, B ＜ a |

There were 450 chickens and ducks in total. Later, half of the chickens were sold and 30 ducks were bought. At this time, the chickens were twice as many as the ducks. How many chickens and ducks were there?

There are x chickens and 450 ducks
After selling half of the chicken and buying 30 ducks, the chicken is twice as big as the duck, so the equation x / 2 = 2 (450-x + 30) can be formulated, and the solution x is 384. So there are 384 chickens and 66 ducks

Given that the maximum value of the function y = a-bcosx (b > 0) is 3 / 2 and the minimum value is only - 1 / 2, find the function y = 2asin (- 3b)
It is known that the maximum value of the function y = a-bcosx (b > 0) is 3 / 2 and the minimum value is only - 1 / 2. The minimum positive period and monotone interval of the function y = 2asin (- 3bx) are obtained

y=a-bcosx
Maximum = a + B = 3 / 2,
Minimum = A-B = - 1 / 2
The solution is: a = 1 / 2, B = 1
y=2asin(-3bx)=sin(-3x)=-sin3x
Minimum positive period T = 2 π / 3
Monotone decreasing interval: (2k π / 3 - π / 6,2k π / 3 + π / 6)
Monotone increasing interval: (2k π / 3 + π / 6,2k π / 3 + π / 2)

I hope you can help me
1. A traveler walks from 3 p.m. to 8 p.m. on the level road first, and then goes up the mountain. When he reaches the top of the mountain, he goes down the slope according to the original road, then goes down the level road, and returns to the original starting point. It is known that his speed on the level road is 4 kilometers per hour, that on the mountain is 3 kilometers per hour, that on the downhill is 6 kilometers per hour, and that when he returns to the level ground, he still keeps walking 4 kilometers per hour. How many kilometers did he walk

Let X be a level road and y be a slope road
x/4+y/3+y/6+x/4=5
===>0.5x+0.5y=5
===>x+y=10
So I walked 10 * 2 = 20km in total. Pay attention to the round trip