If the solutions of equations 1, 4x + y = K + 12, x + 4Y = 3 about XY satisfy 0 < x + y ≤ 1, the range of K is fast and accurate, and the higher the score is

If the solutions of equations 1, 4x + y = K + 12, x + 4Y = 3 about XY satisfy 0 < x + y ≤ 1, the range of K is fast and accurate, and the higher the score is

4x+y=k+1
x+4y=3
Add the above formula: 5x + 5Y = K + 4
0＜x+y≤1
0

12xy − 4x2y3 + 4y2 − X3 in ascending order of X is______ ．

The terms of polynomial 12xy-4x2y3 + 4y2-x3 are 12xy, - 4x2y3, 4y2, - X3, which are arranged as 4y2 + 12xy-4x2y3-x3 according to the ascending power of X. so the answer is: 4y2 + 12xy-4x2y3-x3

Cube of X squared-3 + cube of 2XY squared-y, arranged by the ascending power of X
There is another question, which is also arranged by the ascending power of X
The square of 2x - the square of Y + the cube of xy-4x, the cube of Y
Thank you first

Cube of X squared-3 + cube of 2XY squared-y, arranged by the ascending power of X
-3x^3-y^3+2xy^2+x^2
The square of 2x - the square of Y + the cube of xy-4x, the cube of Y
-y^2+xy+2x^2-4x^3y^3

The four squares of X - the four squares of Y + the cube of 3x, the square of y-2xy - the square of 5x, and the cube of Y are arranged according to the ascending power of X and the ascending power of Y

In ascending order of X
-y^4-2xy²-5x²y³+3x³y+x^4
In ascending order of Y
x^4+3x³y-2xy²-5x²y³-y^4