1) ABC is a triangle where M is the midpoint of segment BC.

MD and ME are two bisectors of triangles AMB and AMC respectively.

If AM= m; BC = a . Then DE = ???

2)\(\dfrac{1}{\left(x+29\right)^2}+\dfrac{1}{\left(x+30\right)^2}=\dfrac{5}{4}\)

What is the product of all real solutions to the equation above?

3) The sum of all possible natural numbers n such that

\(n^2+n+1589\) is a perfect square is.....

4) Given that x is a positive integer such that x and x+99 are perfect squares

The sum of integer x is ...

5)The operation @ on two numbers produces a number equal to their sum minus 2. The value of

(...((1@2)@3....@2017)

6) Given f(x)=\(\dfrac{x^2}{2x-2x^2-1}\)

=> \(f\left(\dfrac{1}{2016}\right)+f\left(\dfrac{2}{2016}\right)+f\left(\dfrac{3}{2016}\right)+...+f\left(\dfrac{2016}{2016}\right)\)

Các bn giúp mk vs >>> tks nha!!!

Question 1:
The least common multiple of 330; 65; 15 is 

Question 2:
Given seven numbers: 25; 17; 39; 43; 239; 1021; 1023.
The composite numbers are  
(Write numbers in order from the least to the greatest and use ";")

Question 3:
The common factors of 18 and 27 are 
(Write numbers in order from the least to the greatest and use ";")

Question 4:
Given the set of even numbers: {2; 4; 6; …; 100}.The number of elements is 

Question 5:
Find four integer numbers a,b,c,d such that
a + b + c + d = 1
a + c + d = 2
a + b + d = 3
a + b + c = 4
Answer: (a;b;c;d)=() 

Question 6:
Find a four-digit natural number that is less than 2015.If the thousands digit is erased,the number will be decreased by 9 times. 
Answer:The number is 

Question 7:
Calculate: 1×2+2×3+⋯+100×101=

Question 8:
The  term of the expression A=1-7+13-19+25-31+⋯ is 

Question 9:
Given the expression A= ...
Find the value of n such that 2A+3=
Answer: n=

Question 10:
A natural number has six digits and the units digit is 4.If the units digit is moved to the first row then the number will be increasedby 4 times.The number is