When Wang Kai solved the equation 2x = 5x, he divided x on both sides of the equation and got 2 = 5. Do you know where he was wrong?

When Wang Kai solved the equation 2x = 5x, he divided x on both sides of the equation and got 2 = 5. Do you know where he was wrong?

Through observation, it is not difficult to find that the solution of the equation is x = 0. Dividing x on both sides of the equation is equivalent to dividing 0 on both sides of the equation, which violates the basic property 2 of the equation, so there is a mistake

Let m = {(x, y) | y = 2 ^ x, X belong to R}, n = {(x, y) | x = 1, y belong to R}, then the number of elements of M intersection n is ()

Substituting x = 1 into y = 2 ^ x, the solution is y = 2
There is only one element of M intersecting n, which is (1,2)

1 / 2 + 5 / 6 + 11 / 12 + 19 / 20
It's urgent
Simple operation method is needed

1/2+5/6+11/12+19/20
=(1-1/2)+(1-1/6)+(1-1/12)+(1-1/20)
=4-(1/2+1/6+1/12+1/20)
=4-(1/2+1/2-1/3+1/3-1/4+1/4-1/5)
=4-(1-1/5)
=4-4/5
=3 and 1 / 5 (16 / 5)

If | Mn | ≥ 23, then the value range of K is ()
A. [-34，0]B. (−∞，−34]∪[0，+∞)C. [-33，33]D. [-23，0]

Solution 1: the coordinate of the center of the circle is (3, 2), and the circle is tangent to the x-axis. When | Mn | = 23, the distance between the center of the chord is the largest. From the formula of the distance from the point to the straight line, | 3K − 2 + 3 | 1 + K2 ≤ 1, the solution is k ∈ [− 34, 0]; so a is selected. Solution 2: the combination of numbers and shapes, as shown in the figure, can be sandwiched between two straight lines by the vertical diameter theorem, without taking + ∞, excluding B, considering the interval asymmetry, excluding C, using the slope estimation, so a is selected ．

How much is one to three fourths minus one eighth

Answer: one eighth

The square of y = 2x-4x + 4 is transformed into the form of the square of y = a (x + H) + K

y=2x^2-4x+4=2(x^2-2x+2)=2[(x-1)^2+1]=2(x-1)^2+2

6: The ratios of 1:9:1,0.3:0.2 and 15:10,1:4:1 and 0.8:0.6,7:20 and 2:7 were 9 and 6:1:9:1,0.3:0.2 and 15:10,3:1:4:1 and 0.8:0.6,

6:9=6÷9=2/3
1 / 6: 1 / 9 = 1 / 6 △ 1 / 9 = 3 / 2
So 6:9 = 1:9:6
0.3:0.2=0.3÷0.2=1.5
15：10=15÷10=1.5
So 0.3:0.2 = 15:10
1 / 3:1 / 4 = 1 / 3 △ 1 / 4 = 4 / 3
0.8：0.6=0.8÷0.6=4/3
So 1 / 3:1 / 4 = 0.8:0.6
7：20=7÷20=0.35
2：7=2÷7=2/7
Can't make up proportion

When x is equal to what, there is a minimum value for the tester / 2x-1 / + 3. What is the minimum value?

Because the absolute value of a number is non negative, the minimum absolute value of a number is 0, so the minimum absolute value of a number + 3 is 3. So the minimum x must satisfy 2x-1 = 0, so the solution is x = 0.5

How to calculate (1 / 7 + 9 / 13 × 2.8) × 3 / 13 easily
It's urgent!

=1/7×13/3+9/13×2.8×13/3
=13/21+3×2.8
=13/21+8+2/5
=8+107/105
=9 and 2 / 105

It is known that the polynomial (m-2) x ^ 8-x ^ n + 1 + 3x + n about X is a quartic trinomial about X. find the value graph of M, n

m=2,n=4