Two out of seven is equal to the sum of three molecules of one

1/21+1/14+1/6

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1. (x＋4）÷8=1.
2. Equation x 6 = 6 / X
3. If 2 equals 5, 3 equals 15, 4 equals 225, then what is 5
4. Given the point m (- 4a-8, a + 5) in the plane rectangular coordinate system, the distance from the point m to the X axis is 2 It's urgent. Thank you
5. How much is seven out of thirty minus seven out of thirty
6. Given that a (negative 3a, 5) B (6.2b) is symmetric about y axis and ab is parallel to X axis, the values of a and B are obtained
7. How to solve x-0.36x = 16
8. Let the matrix a be a normal matrix and satisfy the cubic power of a = the quadratic power of 2A. It is proved that the quadratic power of a = 2A
9. Let a be a matrix of order 3, | a | = 0.5, find | (2a) ^ (- 1) - 5A * | =? My solution is as follows: The original formula = | - 4A * | according to | AA * | = | - a | - e |, then | - A * | = | - a | ^ 2 = 0.25 So the above formula = - 1, but the answer is - 2?
10. Let a be a matrix of third order, and | a | = & frac12;; the - 1 power of determinant | (2a) + A * | =? A=4 B=-4 C=2 D=-2 E=-1 F=1
11. F (x) = 5 * x ^ (1 / 3) * (x + 9) ^ (2 / 3) what are the monotone increasing and decreasing intervals of this equation? What are the maximum and minimum values?
12. The number of subsets of set {0,1,2,3,4,5,6,7,8,9} is (); the number of proper subsets is (); the number of nonempty proper subsets is ()
13. 10 times 1 / 11 + 11 times 1 / 12 + +How much is 2000 times 1 / 1999?
14. How to find the intersection point of positive proportion function and inverse proportion function? Why is it a quadratic equation of one variable when it is listed?
15. A simple algorithm of 972 / 18 + 35 * 19
16. Function y = AX-2 (a > O, a is not equal to 1) what is the constant point of the image? Note that X-2 refers to the exponent of A. why is the constant point it?
17. It is known that the square of the reciprocal sum of two unequal real number roots of the equation m + X + (M-3) x + 1 = 0 is equal to 25, and the value of M is obtained
18. Tan (π + a) = - 1 / 2, the value of sin (A-7 π) cos (a + 5 π) can be obtained
19. Given that the parabola y2 = 6x leads a string through the point P (4,1) so that it is bisected at the point P, the equation of the line L where the string lies is obtained
20. It is known that the parabola y2 = 8x, passing through the point P (1,1) leads to a string, which is bisected at p. the linear equation of the string is obtained Do me a favor Be specific. emergency