Comprehensive problems of mathematical algebra a. B is the two real roots of the quadratic equation MX ^ 2 - (Mn + m + 1) x + 4N = 0 with respect to X. C and D are the two real roots of the equation 8y ^ 2 - (2m + 4) y + (5-N) = 0 with respect to y. if a and C are reciprocal to each other, B and D are reciprocal to each other, the values of M and N are obtained

Comprehensive problems of mathematical algebra a. B is the two real roots of the quadratic equation MX ^ 2 - (Mn + m + 1) x + 4N = 0 with respect to X. C and D are the two real roots of the equation 8y ^ 2 - (2m + 4) y + (5-N) = 0 with respect to y. if a and C are reciprocal to each other, B and D are reciprocal to each other, the values of M and N are obtained

Because a = 1 / C, B = 1 / d
So a + B = (Mn + m + 1) / 2m AB = 4N / m
1/a+1/b=(a+b)/ab=(mn+m+1)/8n=(m+2)/8
So (Mn + m + 1) / 8N = (M + 2) / 8
And 1 / AB = m / 4N = (5-N) / 8
M, n can be obtained from the simultaneous equations
The operation is quite simple

A and B stores buy a commodity at the same unit price of 200 yuan. Store a sells it at a 30% profit increase, and store B sells it at a 20% profit increase. As a result, the number of items sold by store B is twice that of store a, and the total profit is 8000 yuan more than that of store A. how many items do store a and store B sell?

Suppose store a sells x items, then store B sells 2x items. According to the meaning of the question, we get 200 × 20% · 2x-200 × 30% · x = 8000, and we get x = 400. Answer: if store a sells 400 items, then store B sells 800 items

Binary linear equations in junior high school mathematics
I saw a problem in the textbook
Given the quadratic equation 3x-4y = 5 (1), the equation is written in the form of algebraic expression y containing X
What is the algebraic expression of X? I'm a little confused

The algebraic expression of X means that the algebraic expression contains only the unknown number X
Problem solving method: take x as known number, y as unknown number, and solve the equation
3x-4y=5
3x-5=4y
y=(3x-5)/4=3x/4-5/4

Compare the size of - 17 / 16 and - 16 / 17 by rational division
It's better to have an explanation,

-17/16-1
-17/16

Can you compare the size of - 119 / 120 and 120 / 121 with the division of rational numbers?

If the quotient is greater than 1, the divisor is greater than the divisor. If the quotient is less than 1, the divisor is greater than the divisor

Division of rational numbers
1. -0.5÷7/8×（-5/4）
2. （-7）÷（-3/2)÷（-7/5）
3. 3 and 1 / 3 △ (- 2 and 1 / 3) △ (1 and 1 / 5)
4. 1÷【（-1）÷4/5】
5. （-2/3）×8/27×（-1.5）÷（-16/9）
6. (- 36) / (1 and 1 / 2) × (- 2 / 3)
7. (-2/3)×（-8/5）÷（-0.25）
Here are some calculation problems. There should be a process. Please do me a favor~~~~~~~

1.-0.5÷7/8×（-5/4）
=-1/2×8/7×（-5/4）
=5/7
2.（-7）÷（-3/2)÷（-7/5）
=（-7）×（-2/3）×（5/7）
=2/15
3.3 and 1 / 3 △ (- 2 and 1 / 3) △ (1 and 1 / 5)
=10/3÷（-7/3）÷（6/5）
=10/3×（-3/7）×（5/6）
=-25/21
4.1÷【（-1）÷4/5】
=1÷【（-1）×5/4】
=1÷（-5/4）
=1×（-4/5）
=-4/5
5.（-2/3）×8/27×（-1.5）÷（-16/9）
=（-2/3）×8/27×（-3/2）×（-9/16）
=-（2/3×8/27×3/2×9/16）
=-6/5
6. (- 36) / (1 and 1 / 2) × (- 2 / 3)
=（-36）÷3/2×（-2/3）
=（-36）×2/3×（-2/3）
=16
7.(-2/3)×（-8/5）÷（-0.25）
=（-2/3）×（-8/5）÷（-1/4）
=（-2/3）×（-8/5）×（-4）
=-64/15

If you can calculate simply, you need to calculate simply
8 out of 17 divided by 9 + 1 out of 9 × 8 out of 17
It's tonight
October 9th

8 / 17 divided by 9 is 8 / 17 times 1 / 9
The original formula is: eight seventeen times one ninth plus eight seventeen times one ninth
It's two times eight seventeen times one ninth
Then work it out~

Simple calculation and calculation
1.9999999×8888888÷6666666

（9×1111111）×（8×1111111）÷（6×1111111）＝9×8÷6×1111111＝13333332

Division of quadratic radical. Simplification
4√4/9

=4×2/3
=8/3

On Division
The sum of divisor, divisor, quotient and remainder is 71. What are the known divisor 3, divisor, quotient and remainder?

The quotient is a and the remainder is B
3a+b+3+a+b=71
2a+b=34
B can only be 1,2
2A is even, so B is even
b=2
a=16
The divisor is 50, the quotient is 16, and the remainder is 2