If | X-1 | = 2 |, y | = 4 and XY > 0x + y is equal to

If | X-1 | = 2 |, y | = 4 and XY > 0x + y is equal to

|x-1|=2|y|=4
There are x = 5 or x = - 3, y = ± 2
Because XY > 0
So x = 5, y = 2 or x = - 3, y = - 2
So x + y = 7 or - 5

When x + y = 5, xy = 2, what is (X-Y) equal to?

(x+y)²=5²
x²+y²+2xy=25
x²+y²=25-2xy=21
(x-y)²
=x²+y²-2xy
=21-4
=17
So X-Y = - √ 17 or √ 17

The square of x plus the square of Y is 12, xy = 1.5, x + y

(x+y)²
=x²+y²+2xy
=12+3
=15
So x + y = - 15 or 15

Know the temperature, how to find the speed of sound, list the formula

Theoretical value of sound propagation velocity in air
V theory is equal to (1 + T / 273.15) square root times 331.45
331.45 is the speed of sound at 0 degrees
T is the thermodynamic value of known temperature, which is the general temperature value plus 273.05
25 degrees
25 + 273.15 = 298.15 (if you are satisfied with my reply, please click "praise" in the lower left corner.)

Find 2 ^ (x-1) and log 2 (x-1) symmetric linear equations
Hope to have a detailed process. Detailed!

2 ^ X and log2 (x) are symmetric with respect to y = X. if both figures are shifted one unit to the right, then the axis of symmetry should also be shifted one unit to the right with the same slope and passing through (1,0) point. Therefore, the equation of symmetric straight line is y = X-1

One third and one sixth add up to the sum of one thirty-six
One third plus one sixth plus one tenth plus one fifteenth plus one twenty-one plus one twenty-eight plus one thirty-six

The original formula is 1 / 3 + 1 / 6 + 1 / 10 + 1 / 15 + 1 / 21 + 1 / 28 + 1 / 36,
Step by step, 1 / 3 + 1 / 6 = 1 / 2
1/2+1/10=3/5
3/5+1/15=2/3
2/3+1/21=15/21
15/21+1/28=60/84+3/84=63/84=3/4
3/4+1/36=28/36=7/9
The final result is 7 / 9

To make the output value y greater than 100, what is the minimum positive integer x? Even number * 5 of positive integer equals output y; odd number * 4 + 13 of positive integer x equals output y

From the theme
When x = 2n, y = x * 5
When x = 2n + 1, y = x * 4 + 13
If y = x * 5 > 100, x = 22
If y = x * 4 + 13 > 100, x = 23
So the minimum positive integer of X is 22

One yuan to the power!
A and B vehicles run from a and B at the same time. The meeting point of the two vehicles is 8km away from the midpoint of a and B. It is known that the speed of a vehicle is 1.2 times that of B vehicle, so the distance between a and B is calculated
On Tomb Sweeping Day, teachers and students of a certain school lined up in two columns to go to the martyrs' cemetery. They moved forward at the speed of 4km / h. The liaison officer at the end of the team immediately sent the leader's rule to the Secretary of the Youth League Committee at the head of the team. After that, he immediately returned to the end of the team and spent 14.4min together. The speed of the liaison officer is 6km / h. can you calculate the length of the team?

The distance between the two places is x km
X*(1.2-1)=8+8
0.2X=16
X=16÷0.2
X=80
The distance between the two places is 80 kilometers
The team is x km long
X/(4+6)+X/(6-4)=14.4÷60
X/10+X/2=0.24
3X/5=0.24
X=0.4
Team = 0.4km = 400m

1,2,3,4,5,6,7,8,9,10,11,12, plus the sign, so that the sum of them equals 0
1,2,3,4,5,6,7,8,9,10,11,12, plus a positive or negative sign, make their sum equal to 0

1+2+3+4+5-6+7+8+9-10-11-12=0

Given the square of a + 5a-1 = 0, find the square of a + 1 / 2 of a and the value of a + 1 / 2 of A

Square of a + 5a-1 = 0
Divide both sides by A
a+5-1/a=0
a-1/a=-5
Two sides square
a²-2+1/a²=25
∴a²+1/a²=27
a²+2+1/a²=29
(a+1/a)²=29
∴a+1/a=±√29