Between 10 and 30, find out three prime numbers and make their sum equal to 63, namely 63 = () + () + ()

Between 10 and 30, find out three prime numbers and make their sum equal to 63, namely 63 = () + () + ()

17,19,37

The perimeter of a quadrilateral is 48CM. It is known that the first side is a & nbsp; cm, the second side is 3cm longer than twice the first side, and the third side is equal to the sum of the first and second sides. (1) write the formula for the length of the fourth side; (2) when a = 3cm or a = 7cm, can you still get a quadrilateral? What shape is the figure at this time?

(1) ∵ the first side length is ACM, according to the meaning of the title: the second side length is (2a + 3) cm, the third side length is (a + 2A + 3) cm, and the perimeter of the quadrilateral is 48CM, ∵ the fourth side length is: 48-a - (2a + 3) - (3a + 3), = 48-a-2a-3-3a-3, = 42-6a (CM); (2) when a = 3, the edges of the four sides

Evaluation of Tan π / 8 + cos π / 8
Evaluation,

tanπ/4=1=2tanπ/8/(1-tan²π/8)
Let Tan π / 8 = a
2a/(1-a²)=1
a²+2a-1=0
a=tanπ/8>0
So a = - 1 + √ 2
cosπ/4=√2/2=2cos²π/8-1
cos²π/8=(√2+2)/4
cosπ/8=√(√2+2)/2
So the original formula = - 1 + √ 2 + √ (√ 2 + 2) / 2

It is known that there are two unequal real roots for the quadratic equation of one variable with respect to X to the power of MX "2" (2m + 1) x + m + 2 = 0

There are two unequal real roots
So the discriminant is greater than 0
(2m+1)²-4m(m+2)>0
4m²+4m+1-4m²-8m>0
4m

Given that the function y = (M2-2) XM2 + m − 3 is an inverse scale function and its image is in the first and third quadrants, then M=______ ．

∵ function y = (M2-2) XM2 + m − 3 is an inverse scale function, ∵ M2 + M-3 = - 1, the solution is m = 1 or - 2, and ∵ its image is in the first and third quadrant, ∵ M2-2 > 0, ∵ M = - 2, so the answer is: - 2

The sum of 6 times of X and 14.8 is 16.6. How to solve the equation

6x+14.8=16.6
Solution: 6x = 16.6-14.8
x=1.8÷6
x=0.3

Understanding the concept of high school function
Please explain this sentence in simple language: "f (a) means that when the independent variable x = a, the value of function f (x) is a constant, f (a) is a specific value of F (x): F (x) is a function of the independent variable x, generally it is a variable." also give me a few examples to see

X is the domain of definition, y is the range of values, and F is the corresponding rule from X to y, that is, f (x) = y
For example:
Y = x + 1
When x = 1, y = 1 + 1 = 2
It can also be written as f (1) = 2
You can think about it slowly. In fact, it's not difficult. If you still don't understand, send me a message

If a times 5 out of 16 equals B times 5 out of 8, then a: B equals (): (), what is the ratio between a and B?

A × 5 / 16 = B × 5 / 8
a: B = 5 / 8: 5 / 16
a：b=10:5
a：b=2:1
A is proportional to B
Please click the [select as satisfactory answer] button below

How to calculate the number of subsets of a set
The number of subsets of the set is 2 ^ x, how is this calculated? I hope I can answer it in simple language, but I can't understand any binomial at all

Solving by multiplication theorem
Our method of constructing subsets of sets can be decomposed into x steps
1) There are two ways to determine whether the first element in the original set is in the subset
2) There are two ways to determine whether the second element in the original set is in the subset
...
x) There are two ways to determine whether the x-th element in the original set is in the subset
According to the principle of multiplication, there are 2 ^ x methods

How to calculate 15 ° 4'3 ″ / 7 + 56 ° 32'54 ″?

15°4′3″/7+56°32′54″
=14°64'3″/7+56°32′54″
=14°63'63″/7+56°32′54″
=2°9'9″+56°32′54″
=58°41′63″
=58°42′3″