7 of 9 / 11 of 5 + 5 of 11 * 2 of 9 simple and convenient

7 of 9 / 11 of 5 + 5 of 11 * 2 of 9 simple and convenient

7 of 9 / 11 of 5 + 5 of 11 * 2 of 9
=7 of 9 * 5 of 11 + 5 of 11 * 2 of 9
=5 out of 11 * (7 out of 9 + 2 out of 9)
=5 / 11 * 1
=5 out of 11

How to do 11 / 6-2 / 9 + 1 / 6-7 / 9?

11/6-2/9+1/6-7/9=11/6+1/6-(2/9+7/9)=2-1=1

How can 10 out of 9 minus 8 out of 9 be simply calculated? There should be a formula

10 out of 9 minus 8 out of 9
= 10/9 - 8/9
=2/9

X minus 10% x = 9, please write the equation

x - 10%x = 9
x - 0.1x = 9
(1 - 0.1)x = 9
0.9x = 9
x = 9÷0.9
x = 10

It is proved that when n is an integer, the square difference (2n + 1) ^ 2 - (2n-1) ^ 2 of two consecutive odd numbers is a multiple of 8
To analyze,

（2n+1）^2-（2n-1）^2
=4n^2+4n+1-4n^2+4n-1
=8n
It must be a multiple of eight

dy/dx=x/2y dy/dx=x+y

dy/dx=x/2y
2y dy=x dx
Integral of both sides at the same time is as follows:
Y ^ 2 = x ^ 2 / 2 + C (C is constant)
dy/dx=x+y
Let t = x + y
Then DT / DX = 1 + dy / DX
The original formula is as follows:
dt/dx-1=t
dt/dx=t+1
dt/(t+1)=dx
Integral of both sides at the same time is as follows:
Ln|t + 1| = x + C1 (C1 is a constant)
T + 1 = CE ^ x (C is constant)
Then x + y + 1 = CE ^ x
y=Ce^x-x-1

How to do this question 11 * 43 + 22 * 18 + 33 * 7?
I'm in a hurry

11*43+22*18+33*7
=11(43+2*18+3*7)
=11(43+36+21)
=11*100
=1100

From the first four terms of the sequence: 3 / 2,1,5 / 8,3 / 8, the general term formula is concluded

As Jessica said, A1 = 12 / 8a2 = 8 / 8a3 = 5 / 8a4 = 3 / 8a2-a1 = - 4 / 8a3-a2 = - 3 / 8a4-a3 = - 2 / 8A (n + 1) - an is the arithmetic sequence of the first term - 1 / 2 Tolerance 1 / 8, which is the rule. The topic only requires the general term formula to be induced, so the algorithm does not repeat (first calculate the general term formula of a (n + 1) - an, then stack) the last result

A cone is surrounded by several planes and surfaces. There are several intersecting lines, among which there are several straight lines and several curves

A plane, a curved surface, a common line of intersection, is a curve

0 degree ice and 0 degree water
Is it correct to say that "0 degree ice must be more water-cooled than 0 degree ice"? Why?

See how to understand
The key word is "cold"
It's the same to understand this word in terms of temperature
But it's very different to understand it in terms of human senses
Ice absorbs more heat than water, because it needs to melt first. Of course, it absorbs more heat than water, so it feels "cold."