1.4a^2-b^2+6a-3b2.a^2（b^2-c^2）-c^2（b-c）（a+b）3.20x^2-43xy+14y^24.5x^2+4xy-28y^25.20x^2-43xy+14y^26.3x^2+12x-57.x^2+4x-48.x^2-2xy-35y^29.2x^2-7x-1510.x^4+2x^2-311.(x+y)^2-3(x+y)+212.4x^2-12x+513.x^2+2-3x
问题描述：
1.4a^2-b^2+6a-3b
2.a^2（b^2-c^2）-c^2（b-c）（a+b）
3.20x^2-43xy+14y^2
4.5x^2+4xy-28y^2
5.20x^2-43xy+14y^2
6.3x^2+12x-5
7.x^2+4x-4
8.x^2-2xy-35y^2
9.2x^2-7x-15
10.x^4+2x^2-3
11.(x+y)^2-3(x+y)+2
12.4x^2-12x+5
13.x^2+2-3x
答