用提取公因式法分解因式:-15xy-5x2;
用提取公因式法分解因式:8ab2-16a3b3;
计算:21×3.14-31×3.14=_________.
-15a2+5a=________(3a-1);
因式分【解析】km+kn=_________;
3a2-6ab+a=_________(3a-6b+1);