It is known that 3x-y = 4. If y is represented by an algebraic expression containing x, then y =? In 2x + (one third of Y) = 1, when x = (1 / 2), y =?; when y = 3, x =? Determinant No more formulas

It is known that 3x-y = 4. If y is represented by an algebraic expression containing x, then y =? In 2x + (one third of Y) = 1, when x = (1 / 2), y =?; when y = 3, x =? Determinant No more formulas

(1)y=3x-4
(2) In 2x + (one third of Y) = 1, when x = (1 / 2), y =?; when y = 3, x =?
2x+y/3=1
① When x = 1 / 2
2×1/2+y/3=1
y=0
② When y = 3,
2x+3/3=1
x=0

1. For a rope, 25% of the total length was cut off in the first time, 35% of the total length was cut off in the second time, and the second time was 1 meter more than the first time. How long is the rope?
2. The fruit wholesale department needs to import a batch of fruits, 22% of the total amount for the first time and 1.5 tons for the second time. The total amount of these fruits is 62% for the second time. How many tons are there in total?

1. 1 / (35% - 25%) = 10m
2. 1.5 / (62% - 22%) = 3.75 tons

In the known cuboid abcd-a1b1c1d1, the angle bab1 = angle b1a1c1 = 30 degree
Then: the angle between Aa1 and B1C is?
What is the angle between Ab1 and a1c1?

45,arccos(3/4)

（-3）+（）=0
（）+（-2）=8
（-4+（）=*2
（）+（-5）=-9
Frantic

（-3）+（3）=0
（10）+（-2）=8
（-4）+（6）=2
（-4）+（-5）=-9

1: How to compare the size of root 5 + root 13 and root 3 + root 19?
2: How to simplify the cube root of 7 + 5 times root sign 2
3: The expression of average speed: what are the expressions of T1, T2 and S1, S2 for V1 and V2 respectively?
4: Y = arcsin (SiNx) image^^^^^
Thank you so much^^^
The first question is the first two plus the second two. The third question is two situations. The first is to use V1 and V2 to walk half the time, and the second is to walk half the distance

The bigger one is bigger, the smaller one is smaller
It doesn't seem to have to be simplified
The average speed is the distance divided by the time. The distance is S2 minus S1, and the time is T2 minus T1
There are pictures in the book, I can't send them

Mischievous is reading a 181 page story book and accidentally closes it. He remembers that the sum of the two pages he just finished reading is 81
How many pages are left in the story book
What are the page numbers of the two pages just read by naughty
Why are the correct answers 40 and 41? Can't they be 30 and 51?
How many pages of the story book are left to read?
Why 181-41 instead of 181 minus 81?

If you want to see the meaning of the title clearly, the two pages you have just read mean to turn to the next page after reading this page, and the sum of these two pages is equal to 81. When you read a book, do you turn to the next page after reading page 30? So the answer is to turn to 41 after reading 40, and then close the book, and the sum of these two pages is 81. The last page he read is 41, so there are 181-41 = 140 pages left

It took five seconds for a train to pass a road sign, 20 seconds to pass a 300 meter long bridge, and () seconds to cross an 800 meter long cave

It takes 5 seconds for a train to pass a road sign, which means that it takes 5 seconds for the train to go its own length
It takes 20 seconds to pass a 300 meter long bridge, and it takes 15 seconds for the train to cross the bridge
It takes (800 / 300) * (20-5) + 5 = 45s to completely cross an 800m long cave

We know the fractional equation 1 / x = m / (x + 1) + m / (x-1) about X
(1) If the equation has two unequal real roots, find the value range of M
(2) Finding the value of M which makes the equation have increasing roots
(3) If the original equation has no real root, the value range of M is obtained

The equation (x + 1) (x-1) = MX is solved by itself
It's a waste of time not to do the rest

Super simple math problem!
1. A cat catches up with a mouse. The mouse runs to the edge of the round pond and jumps into the pond. The cat stares at the mouse and runs along the direction of swimming with the mouse. It wants to wait for the mouse to climb onto the bank before catching it. It is known that the running speed of the cat is three times that of the mouse. Please think about it. Is it possible for the mouse to escape?
2. There are five round flower beds with diameters of 3 meters, 4 meters, 5 meters, 8 meters and 9 meters respectively. Now divide these five flower beds into two parts and assign them to two classes for management, so that the areas managed by these two classes are as close as possible. How to divide them?
Please all the immortals come to give advice and write down the detailed steps
It's super simple for prawns!
This friend, don't talk about me, just do it, "just say it, don't practice it"!

If a mouse stays in the water all the time, it will not die. If it goes ashore, it will die, because the cat will catch up with it sooner or later
2 3^2+4^2+5^2+8^2+9^2=195
195/2=97.5
16+81=97
So 3,5,8 are managed by one class, 4,9 by one class

1. If you wrap a rope around a tree for 5 times, it will be 1 / 6 meter. If you wrap a rope around a tree for 1 / 4 times, it will be 3 / 4 meter. Find the length of the rope and the circumference of the tree
2. The road construction team completed the construction of a highway in four days. On the first day, it completed 32% of the total length of the highway. On the second three days, it completed 6:7:4, and on the last day, it completed 8 kilometers less than on the first day. How many kilometers is the total length of the highway?
3. It is said that nine birds have nine heads and one tail, and nine birds have nine tails and one head. Today, there are 580 heads and 900 tails. How many are each of them?
Note: the first problem should be solved by equation. 2.3 problem can be solved by formula

1. If you wrap a rope around a tree for 5 times, it will be 1 / 6 meter. If you wrap a rope around a tree for 1 / 4 times, it will be 3 / 4 meter. Find the length of the rope and the circumference of the tree
Let X be the length of the rope and y be the circumference of the tree
X-1/6=5Y ; X/4-3/4=Y
X-1/6=5X/4-15/4
X/4=15/4-1/6
X=43/3
Y=17/6
2. The road construction team completed the construction of a highway in four days. On the first day, it completed 32% of the total length of the highway. On the second three days, it completed 6:7:4, and on the last day, it completed 8 kilometers less than on the first day. How many kilometers is the total length of the highway?
The total length is x meters
0.32X-(1-0.32)*4X/(6+7+4)=8
0.16X=8
X=50
3. It is said that nine birds have nine heads and one tail, and nine birds have nine tails and one head. Today, there are 580 heads and 900 tails. How many are each of them?
There are x nine headed birds and Y nine tailed birds
9X+Y=580 ； X+9Y=900
8100-81Y+Y=580
80Y=7520
Y=94
X=54