An addition and subtraction problem of mathematical integral There is such a problem, "when a = 2, B = - 2", find the value of polynomial 2 (a ^ - 3AB + 3b) - 3 (- A ^ 2-2ab + 2b). Ma Xiaohu fried a = 2 into a = - 2. Wang Xiaozhen did not copy the wrong problem, but they all made the same result. Do you know what happened? Please explain the reason

An addition and subtraction problem of mathematical integral There is such a problem, "when a = 2, B = - 2", find the value of polynomial 2 (a ^ - 3AB + 3b) - 3 (- A ^ 2-2ab + 2b). Ma Xiaohu fried a = 2 into a = - 2. Wang Xiaozhen did not copy the wrong problem, but they all made the same result. Do you know what happened? Please explain the reason

Is that a ^ 2-3ab + 3B in your first bracket
If it is, it's very simple. You simplify it and find that it has nothing to do with a and B, only with a ^ 2, so 2 or - 2 are no different

On the addition and subtraction of integers
Given a = A & # 179; - 2A & # 178; B + AB & # 178;, B = 3A & # 178; B + 2Ab & # 178; - A & # 178;, and a = 2B + C, find C
There is a question "simplify first, and then evaluate: 9x & # 178; - (4x & # 178; + x-3) + (- 5x & # 178; + 6x-1) - 5x, where x = 2013." Liu Fen wrongly changed "x = 2013" into "x = 2103" when he did the question. But his calculation result is really correct, please explain why
First simplify and then evaluate: 3x & # 178; Y - [2XY & # 178; - 2 (xy-3 / 2 x & # 178; y) + XY & # 178;] + 3xy & # 178;, where x = 3, y = - 1 / 3

⑴A=a³-2a²b+ab²,B=3a²b+2ab²-a²,
A＝2B＋C
C=A-2B
=a³-2a²b+ab²-2（3a²b+2ab²-a²）
=a³-2a²b+ab²-6a²b-4ab²+2a²
=a³-8a²b-3ab²+2a²
⑵9x²-（4x²+x-3)＋﹙﹣5x²＋6x－1﹚－5x
=9x²-4x²-x+3﹣5x²+6x-1-5x
=(9x²-4x²﹣5x²)+(6x-x-5x)+(3-1)
=2
Since there is no X term after the reduction of the original formula, the answer has nothing to do with how much x equals, so his result is still correct
(3) the original formula = 3x & # 178; Y - (2XY & # 178; - 2XY + 3x & # 178; y + XY & # 178;) + 3xy & # 178;
=3x²y-2xy²+2xy-3x²y-xy²+3xy²
=（3x²y-3x²y）+（3xy²-2xy²-xy²）+2xy
=2xy
Substitute x = 3, y = - 1 / 3 to get
Original formula = 2 × 3 × (- 1 / 3) = - 2
May I help you!

On the addition and subtraction of integers
(1) Write any two digit number
(2) Exchange this two digit ten digit number and one digit number to get another number
(3) Find the sum of the two numbers
This formula always holds. What's the law,
If you change it to any three digit number, what's the rule of exchanging hundreds with ones and subtracting two numbers

They're all multiples of 11. Yes, they're all true
Let 2-digit = 10x + y, where x and y are integers greater than or equal to 1 and less than or equal to 9
The two digits after the exchange are 10Y + X
Add two numbers = 11x + 11y = 11 (x + y)
So we have to prove it

Some problems about the addition and subtraction of integers~
Given that y = ax to the 5th power + BX to the 3rd power + CX-1, when x = 2, y = 5, then when x = 2, the value of Y is ()
A.-17 B.-7 C.-3 D.7
If the fourth power of formula 3x - the third power of X + the third power of KX + the second power of X + 2 does not contain the third power of X, then the value of K is ()
It's better to bring some explanation!

When x = - 2, y = 5
That is y = a * (- 2) ^ 5 + b * (- 2) ^ 3 + C * (- 2) - 1 = 5
a*(-2)^5+b*(-2)^3+c*(-2)=5+1=6
When x = 2
y=a*2^5+b*2^3+c*2-1
=-(a*(-2)^5+b*(-2)^3+c*(-2))-1
=-6-1
=-7
Choose B
3x^4-x^3+kx^3+x^2+2
=3x^4+(k-1)x^3+x^2+2
Without x ^ 3
That is, the coefficient of x ^ 3 is 0
That is k-1 = 0, k = 1
The value of K is 1