10 out of 21 / 11 out of 12 * 14 out of 15 =? 1 / (x + 1 and 2 out of 3) = 4 out of 5

10 out of 21 / 11 out of 12 * 14 out of 15 =? 1 / (x + 1 and 2 out of 3) = 4 out of 5

10 of 21 / 11 of 12 * 14 of 15
=10 out of 21 * 12 out of 11 * 14 out of 15
=(3/2)*(11/4)*(5/2)
=165/8
1 / (x + 1 and 2 / 3) = 4 / 5
1=(x+5/2)*(5/4)
1-5/2*5/4=（5/4）x
(-17/8)/(5/4)=x
x=-17/8*4/5=1.7

1 and 7 / 9 x-x = 5 / 21

1 and 7 / 9x-x = 5 / 21
7/9x=5/21
x=5/21*9/7
x=15/49

Given the equation x ^ 2-6x + M = 0 about X, if one root is twice the other root, then the value of M is

According to Weida's theorem, X1 + x2 = - B / A; X1 * x2 = C / A
So there are: X1 + x2 = 6, X1 * x2 = m, and X1 = 2, x2
The solution is X1 = 4, X2 = 2
So m = 2 * 4 = 8

Given that equation 6x2 + 2 (M-13) x + 12-m = 0 has a positive integer solution, then the value of integer m is___ ．

It is known from the meaning of the title that: △ = [2 (M-13)] 2-4 × 6 × (12-m) = 4 × [(M-13) 2-6 · (12-m)] should be a complete square, so (M-13) 2-6 · (12-m) is a complete square, let (M-13) 2-6 · (12-m) = Y2 (y is a positive integer), then m2-20m-y2 + 97 = 0, that is (M-10

The equation 5 + MX = - 2mx is known, where x is an unknown number. (1) if M = - 3, find the solution of the equation; (1) if x = 3 is the solution of the equation, find the value of M

(1) If M = - 3, the original formula is 5-3x = 6x
x=5/9
(2) If x = 3 is the solution of the equation, the original formula = 5 + 3M = - 6m
m=-5/9

When m is an integer, the solution of the equation 1 / 2mx-5 / 3 = 1 / 2 (x-4 / 3) + m is positive

1 / 2mx-5 / 3 = 1 / 2 (x-4 / 3), i.e. 1 / 2mx-3 / 5 = 1 / 2x-2 / 3 ℅ (1 / 2-1 / 2m) x = 2 / 3-3 / 5, i.e. (1-m) x = 4 / 15 × 2, i.e. (1-m) x = 8 / 15  x = 8 / [15 (1-m)]  its solution is a positive number, i.e. 8 / [15 (1-m)] > 0, i.e. 1-m > 0  m < 1  m is an integer  M = 0, - 1, - 2, - 3 The title is not strict

Let us know that (M2 - |) X2 - (M + 1) x + 8 = 0 is a linear equation of one variable with respect to x, and find the value of the algebraic formula 199 (x-2m) + 15 (Note: the number after M and X is the square, and X is the unknown number)

It can be seen from the meaning of the title: m square - 1 = 0 and M + 1 ≠ 0
The solution is: M = 1
Then the original equation can be reduced to - 2x + 8 = 0
The solution is: x = 4
So:
199(x-2m)+15
=199*(4-2)+15
=398+15
=413

The ratio of unknown number to 4 / 5 is equal to 1 / 3 to solve the equation

Let the unknown be XX: (4 / 5) = 1 / 3x = (4 / 5) * (1 / 3) = 4 / 15

X is the unknown number, and we solve the equation,
One quarter x plus two-thirds x equals eleven fifths of seven, four fifths multiplied by x plus one equals sixteen-five, twenty-seven fifths minus seventy-three fifths

12/7、19、20

Solving equations to find unknowns
7.5x - 3 = 5.5 + 6.5

7.5x-3=5.5+6.5
7.5x-3=5.5+6.5+3=15
x=15÷7.5
x=2