If half of the equation X-1 = ax (a is a known number) has no solution, then the value of a should be

If half of the equation X-1 = ax (a is a known number) has no solution, then the value of a should be

Double two on both sides
x-1=2ax
There is no solution for (1-2a) x = 1
So 1-2a = 0
a=1/2

Given that ABCDE multiplied by 4 equals edcba, find the number of ABCDE representatives

I will I will I will

Find the value range of (X Cubic) + 3 (x square) + 2x > 0,

Left = x (x ^ 2 + 3 * x + 2) = x (x + 1) (x + 2)
X0
So the value range is - 2

Looking at his math score statistics, Xiao Ming predicted that if he scored 100 in the next math test, the average score would be 91. If he scored 80 in the next math test,
Xiaoming looks at his math score statistics table and predicts that if he gets 100 points in the next math test, the average math score is 91 points. If he gets 80 points in the next math test, the average math score is 86 points. How many times has Xiaoming got on his math score statistics table?

3 times. When the test is 100, the average is 91, and when the test is 80, the average is 86. That is to say, when the score changes to 20, the average score changes by 5. So this time, there are 4 scores

If x, y ∈ R + and X + y = 8, find: (1) the maximum value of XY; (2) the minimum value of 1 / x + 2 / y

（1）x,y∈R+
x+y>=2√xy
That is 2 √ XY

How much is 3 and 15 / 13 minus 2 and 14 / 13 plus 5 and 13 / 2 minus 1 and 14 / 1

13 out of 3 and 15 = 58 out of 15 (1)
2 and 13 out of 14 = 41 out of 14 (2)
5 and 2 / 13 = 67 / 13 (3)
1 and 1 / 14 = 15 / 14 (4)
(2) - (4) = 26 / 14 (5)
(1) + (3) - (5) = (58 times 13 times 14 + 67 times 15 times 14-25 times 15 times 13) divided by 15 times 14 times 13 = 2730 / 19751

It is known that the inverse scale function y = 3-2m / X decreases with the increase of X in the first quadrant
① When x ＜ 0, which quadrant is the function image in
② Find out the value of the positive integer m satisfying the condition

y=(3-2m)/x
In the first quadrant, y decreases with the increase of X, then 3-2m > 0
When x < 0, y = (3-2m) / x < 0, the third quadrant

Xiao Ming and seven people go on an outing. He uses 20 yuan to buy drinks. The store has Cola milk tea, 2 yuan for coke and 3 yuan for milk tea. If 20 yuan is just used up
(1) How many ways to buy? How many cups of cola and milk tea each?
(2) When each person has at least one drink and at least two milk teas, how many ways to buy them?

1. Three kinds: (1) 2 cups of milk tea * 3 yuan + 7 cups of cola * 2 yuan = 20 yuan
(2) 4 cups of milk tea * 3 yuan + 4 cups of coke * 2 yuan = 20 yuan
(3) 6 cups of milk tea * 3 yuan + 1 cup of coke * 2 yuan = 20 yuan
2. One: 7 cups of cola, 2 cups of milk tea

Find the maximum and minimum values of the function z = x Λ 2 + y Λ 2-xy-x-y in the closed domain D: X ≥ 0, y ≥ 0, x + y ≥ 3
Such as the title

Maximum value: 6, minimum value: 0

A bottle of 2 / 5 kg of beverage. After Xiao Ming drinks some, the ratio of what he drinks to the rest is 2:3. How many kilograms of beverage are left?

There are 2 / 5 ÷ (2 + 3) X3 = 2 / 25x3 = 6 / 25kg left