《2025年启东中学作业本七年级数学上册苏科版徐州专版》

合并同类项:
(1)$6a^{2}+2a-3a^{2}-7a$; (2)$\frac {1}{2}x^{2}-3xy^{2}+4y^{2}+\frac {1}{2}x^{2}+5xy^{2}$;
(3)$3x^{2}y-4xy^{2}-3+5x^{2}y+2xy^{2}+5$; (4)$\frac {1}{3}m^{2}n-\frac {1}{2}mn^{2}-nm^{2}+\frac {1}{6}n^{2}m$;
(5)$(-\frac {1}{3}xy)+(-\frac {2}{5}x^{2})-\frac {1}{2}x^{2}-(-\frac {1}{6}xy)$; (6)$8(a-b)-5(a-b)-7(a-b)$;
(7)$2a^{3}b-\frac {1}{2}a^{3}b-a^{2}b+\frac {1}{2}a^{2}b-ab^{2}$;
(8)$3(n-m)^{2}-7(n-m)+8(n-m)^{2}+6(n-m)$.

答案：
(1)$3a^{2}-5a$
(2)$x^{2}+2xy^{2}+4y^{2}$
(3)$8x^{2}y-2xy^{2}+2$
(4)$-\frac{2}{3}m^{2}n-\frac{1}{3}mn^{2}$
(5)$-\frac{1}{6}xy-\frac{9}{10}x^{2}$
(6)$-4a+4b$
(7)$\frac{3}{2}a^{3}b-\frac{1}{2}a^{2}b-ab^{2}$
(8)$11(n-m)^{2}-(n-m)$