1) x²y+5xy²-3x²y+6xy²-2xy²+3x²y
x²y+9xy²
xy·(x+9y)
2) (5a²+3ab)+(b²-2ab)-(a²+3b²-4ab)+(a²-b²)
5a²+3ab+b²-2ab-(a²+3b²-4ab)+a²-b²
5a²+3ab-2ab-a²-3b²+4ab+a²
5a²+5ab-3b²
3) (6m+3n)-(2n+3m+5)-(3m-4n-6)
6m+3n-2n-3m-5-3m+4n+6
0+5n+1
6n+1
4) (13m²+2mn-n²)-(2m²+3mn+4n²)-(10m²+2mn)
13m²+2mn-n²-2m²-3mn-4n²-10m²-2mn
m²-5n²-3mn
succes!!!!
