15x³-6x²y+3xy²-2y²-7写成两个多项式的和,使其中一个多项式不含y

Question

【15x³-6x²y+3xy²-2y²-7】写成两个多项式的和,使其中一个多项式不含y

Answer 1

15x^3-6x^2y+3xy^2-7 
=3X(5X^2-2XY+Y^2)-7
 
15x^3-6x^2y+3xy^2-7 
=3x(5x^2-2xy+y^2)-7 
=3x[(x-y)^2+4x^2]-7 
=[3x(x-y)^2]+[12x^3-7]
 

15x^3-6x^2*y+3xy^2-7 
=(15x^3-7)+(-6x^2*y+3xy^2) 

 
15x^3-6x^2*y+3xy^2-7 
=(15x^3-7)+(3xy^2-6x^2*y)
4x^2-3xy-2+5y^2
=(4x^2-2)-(3xy-5y^2)