The method of extracting common factor 6（m-n）³-12（n-m）² 2（y-x）²+3（x-y） mn（m-n）-m（n-m）² There must be a complete process~ Because I can't do these three questions, I want to understand them~

The method of extracting common factor 6（m-n）³-12（n-m）² 2（y-x）²+3（x-y） mn（m-n）-m（n-m）² There must be a complete process~ Because I can't do these three questions, I want to understand them~

6（m-n）³-12（n-m）²
Original formula = 2 (m-n) ^ 2 * (m-n-2)
2（y-x）²+3（x-y）
Original formula = 2 (X-Y) ^ 2 + 3 (X-Y)
=(x-y)(2x-2y+3)
mn（m-n）-m（n-m）²
Original formula = Mn (m-n) - M (m-n) ^ 2
=m(m-n)(n-2m+2n)
In fact, the key to these three questions is that the landlord can't find the common factor, right?
It's very simple
Square of A-B = square of B-A!

The calculation of common factor method
1.m（m-n）²-n（n-m）²
2.（a-2）²-（2-a）
3. First decompose the factor, and then evaluate: a (8-A) + B (A-8) - C (8-A), where a = 1, B = half, C = half

1.m（m-n）²-n（n-m）²=m（m-n）²-n（m-n）²=（m-n）²(m-n)=(m-n）^32.（a-2）²-（2-a）=（a-2）²+（a-2）=（a-2）(a-2+1)=（a-2)(a-1)3.a（8-a）+b（a-8）-c（8-a）=-a（a-8）+...

The function y = csinx is a general solution of the differential equation y '' + y = 0, B special solution D is not a solution,

Substituting a function into a differential equation, y = csinx
∴y'=Ccosx,y''=-Csinx
Substituting, we get - csinx + csinx = 0 = 0
Left = right
Choose C

It is known that f (x) = {1, X is greater than or equal to 0 = - 1, X

It's better to have a classified discussion
1. When x ≥ - 2, the inequality is equivalent to: 2x + 2 ≤ 5, - 2 ≤ x ≤ 1.5
2. When x

94 × 1999-93 × 2000 should be calculated simply and simply

In the process of writing

The problem of sequence of higher one! We know that every item of sequence {an} is positive and satisfies the following conditions: A0 = 1, an 1 = 1 / 2An * (4-an). (n belongs to n)
Analytically, after taking logarithm on both sides of the equation, it is transformed into a (n + 1) = pan + Q, and then solved by undetermined coefficient method. What is the meaning? How to take logarithm?

In this problem, we need to judge the range of an, then we can use logarithm and undetermined coefficient method
a0=1 0

How to solve 8.7x-3.4x = 5.406?

8.7x-3.4x=5.406
5.3x=5.406
x=5.406/5.3
x=1.02

A barrel of oil weighs 32 kg. After 60% of the oil is poured out, it weighs 14 kg. How many kg is the original oil in this barrel?
Write clearly with the solution of the equation

(32-14)÷60%=30Kg

Piecewise function f (x) = SiNx / x, X is not equal to zero = 0, x = 0
Then x = 0 is ()
A. Removable discontinuities B. jumping discontinuities C. discontinuities of the second kind D. continuous points

Limsinx / x = 1

The solution of the equation 2 / 1X = - 2 + a about X is 2 larger than that of the equation 5x-2a = 10 about X

1/2X=-2+a
==>x1=-4+2a
5X-2a=10
==>x2=(10+2a)/5
x1-x2=-4+2a - (10+2a)/5=2
The solution is a = 5
The law of solving the equation,
1. General division, which converts all the data into integer expressions, is to multiply both sides of the equal sign by the common multiple of the denominator at the same time
2. Move the term containing x to one side of the equation and the constant term to the other side
For example, if you move - x to the right with - x + y = 5, you must add a symbol before - x, so it becomes + X, that is, y = 5 - (- x) + X. similarly, move 5 to the left with X-Y - (5) = x-y-5 = 0
Note that if both sides of the equation add, subtract, multiply and divide the same number, the equation still holds