When x is equal to, 3x-7 and - 2x-9 are opposite

When x is equal to, 3x-7 and - 2x-9 are opposite

-(3x-7)=-2x-9
3x-7=2x+9
x=16

If 7-3x and 4 are opposite numbers, then x is equal to

7/2-3x=-4
Multiply two sides of the equation by two
7-6x=-8
-6x=-8-7
-6x=-15
x=5/2

3 / 4 x + 1 / 2 x is equal to 25, to the whole!

3 out of 4 x + 1 out of 2 x is 25
3x/4+1x/2=25
3x/4+2x/4=25
5x=100
x=20

If sin (PI - α) - cos (- α) = half, then Sin & # 179; (π + α) + cos & # 179; (2 π - α)=

The solution is sin (π - α) - cos (- α) = 1 / 2
So Sina cosa = 1 / 2
Square 1-2sinacosa = 1 / 4
That is, sinacosa = 3 / 8
So Sin & # 179; (π + α) + cos & # 179; (2 π - α)
=[-sina]³+[cos(-a)]³
=-sin³a+cos³a
=cos³a-sin³a
=(cosa-sina)(cos²a+sinacosa+sin²a)
=-(sina-sina)(1+sinacosa)
=-（1/2)(1+3/8)
=-1/2×11/8
=-11/16

Math answers to winter vacation homework in grade three of primary school
First find the rule, and then fill in the appropriate number in the space
5,45 13,63 （）,42 9,（）
25,9 91,9 56,6 81,7
Here are four groups of numbers, two up and two down. It's not easy to check. I hope I can understand it. I can't understand my children's homework. I ask for help
I'm sorry, can you tell me why

The quotient above and below is the same, for example
Five at 25 on the left is five, and nine at 45 on the right is five
13 at 91 equals 7, and 9 at 63 on the right equals 7
and so on
Six equals seven in 42
So 56 with 7 equals 8, and the first blank is 8
Nine equals nine
So 7 times 9 equals 61, so the second blank is 63
Thank you, please support the original

The natural number is arranged as follows, then 15125 should be arranged in which line and which line?
one
2 3 4
5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 22 23 24 25 26 27 ……………………………………………………………………………
one
2 3 4
5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 22 23 24 25 26 27 ……………………………………………………………………………

The number of the last line you gave should be 17 18 19 20 21 22 24 25, 15125. This number should be 241 in line 123, and the last number in line n is n & # 178; &# 178; √ 15125 = 122.98, so there are 122 whole lines before 15125. The last number in line 122 is 122 * 122 = 1488415125 in line 12

For integers a and B, if a △ B = C, then a can be divided by B
1. Integers include natural numbers and negative integers
2. For integers a and B, if a △ B = C, then a can be divided by B
3. Any positive integer whose maximum factor is equal to its minimum multiple
4. Numbers divisible by 6 and 8 must be divisible by 48
5. If the positive even number is expressed as 2n, then the positive odd number can be expressed as 2N-1,. ()
6. The characteristic of numbers divisible by 11 is that the difference between the sum of the first few digits and the sum of the last few digits can be divisible by 11
7. Positive integers can be divided into two categories: prime and composite
The prime factor of 8.12 is 2,3
9. If two numbers are prime, then both numbers are prime
10.5km is five sixths of 6kg
Two thirds out of two tons is equal to Four Thirds out of two tons
12. The simplest fraction cannot be reduced to an integer
Very urgent!

X, and 0
We didn't say C was an integer
It's all about yourself
XX, 24 does not conform
√
Is the sum of odd digits equal to the sum of even digits
One more
√
Three and four are not
Different units cannot be compared
√
This is a corollary of the simplest definition of fraction
&Hope to adopt

4, 7, 12, 19, 32, what's next
Please give a detailed solution

It's 63 or 51
The rule of 51 is 7 = 3 + 4, 12 = 7 + 4 + (4-3) 19 = 12 + 7 + (7-4-3) 32 = 19 + 12 + (12-7-4), so the next number is 51 = 32 + 19 + (19-12-7)
Don't worry, grade two

The sum of four continuous natural numbers is a three digit number between 400 and 440, which can be divided by 9. How many are these four continuous natural numbers

The multiple of 9 between 400 and 440 is 405414423432
This number must be even, but it can't be a multiple of 4, so it's only 414
414 △ 4 = 103.5, so the four numbers are 102103104105
(432 △ 4 = 108)

Mathematics: n-th root
The fourth root of 81
Who is the fourth root of 256
-The third root of 27
Who is the quintic root of 32
If the nth power of X is equal to a, then what is x called a
When n is an odd number, how many? Of the n-th root of the real number a are represented by symbols-
When n is an even number, how many roots of the positive number a to the nth power? They are? Expressed by symbols-
Do negative numbers have even roots? What are any roots of 0?

The fourth root of 81 is ± 3
± 4 is the fourth root of 256
-The third root of 27-3
2 is the quintic root of 32
If the nth power of X is equal to a, then x is called the nth root of A
When n is odd, there is one root of the real number a to the nth power, which is denoted by the sign n √ a
When n is an even number, there are two roots of the positive number a to the nth power
Negative numbers have no even root, any root of 0 is 0