1. (0,3а-1,2b)+(a-b)-(1,3a-0,2b) = 0,3а-1,2b+a-b-1,3a+0,2b = -2b
2. (11p³-2p²)-(p³-p²)+(-5p²-3p³) = 11p³-2p²-p³+p²-5p²-3p³= 7p³-6p²
3. (5x²+6x³)+(x³-x²)-(-2x³+4x²) = 5x²+6x³+x³-x²+2x³-4x²=9x³
4. (-2x³+xy²)+(x²y-1)+(x²y-xy²-3x³) = -2x³+xy²+x²y-1+x²y-xy²-3x³ = -5x³+2x²y-1
5.(3x²+5xy+7x²y)-(5xy+3x²)-(7x²y-3x²) = 3x²+5xy+7x²y-5xy-3x²-7x²y+3x² = 3x²
6. (8a²-10ab-b²)+(-6a²+2ab-b²)-(a²-8ab+4b²) = 8a²-10ab-b²-6a²+2ab-b²-a²+8ab-4b² = a²-6b²