Respuesta:
21. 12x²+2y²+16xy
22. 18y²
23. x²y²+xy³+x³yz+x²y²z+xy²+y³+x²yz+xy²z
24. x²+5xy²-x²y+y²
Explicación paso a paso:
(x+y)²-(4xy-6x(2x+3y))-(x-y)(x+y)
x²+2xy+y²-4xy+12x²+18xy-x²+y²
12x²+2y²+16xy
(4x-3y)²-(4x-3y)(4x+3y)+24xy
16x²-24xy+9y²-16x²+9y²+24xy
18y²
(xy+y)(y+xz)(x+y)
(xy²+x²yz+y²+xyz)(x+y)
x²y²+xy³+x³yz+x²y²z+xy²+y³+x²yz+xy²z
x(x+y²)-y(x²-y)+4xy²
x²+xy²-x²y+y²+4xy²
x²+5xy²-x²y+y²
