1. 计算:
(1)$(-3a^{2})^{3}· a^{3}-(5a^{3})^{3}$; (2)$(-2xy)(3x^{2}-2xy-4y^{2})$;
(3)$(3x-2)(2x+y+1)$; (4)$(m-n)(m^{2}+mn+n^{2})$.
(1)$(-3a^{2})^{3}· a^{3}-(5a^{3})^{3}$; (2)$(-2xy)(3x^{2}-2xy-4y^{2})$;
(3)$(3x-2)(2x+y+1)$; (4)$(m-n)(m^{2}+mn+n^{2})$.
答案:1. (1) $-152a^{9}$ (2) $-6x^{3}y + 4x^{2}y^{2} + 8xy^{3}$
(3) $6x^{2} + 3xy - x - 2y - 2$ (4) $m^{3} - n^{3}$
(3) $6x^{2} + 3xy - x - 2y - 2$ (4) $m^{3} - n^{3}$
2. 计算:
(1)$(-x^{2}y)^{2}-x(3x^{2}-x^{3}y^{2}+1)$; (2)$x(2x-3)+(3-x)(1-5x)$;
(3)$(3m+1)(2m-3)-(6m-5)(m-4)$; (4)$(x-1)(2x+1)-(x-5)(x+2)$.
(1)$(-x^{2}y)^{2}-x(3x^{2}-x^{3}y^{2}+1)$; (2)$x(2x-3)+(3-x)(1-5x)$;
(3)$(3m+1)(2m-3)-(6m-5)(m-4)$; (4)$(x-1)(2x+1)-(x-5)(x+2)$.
答案:2. (1) $2x^{4}y^{2} - 3x^{3} - x$ (2) $7x^{2} - 19x + 3$
(3) $22m - 23$ (4) $x^{2} + 2x + 9$
(3) $22m - 23$ (4) $x^{2} + 2x + 9$
3. 解方程:
(1)$(x-3)(x-2)+18=(x+9)(x+1)$;
(2)$2x(3x-5)-(2x-3)(3x+4)=3(x+4)$.
(1)$(x-3)(x-2)+18=(x+9)(x+1)$;
(2)$2x(3x-5)-(2x-3)(3x+4)=3(x+4)$.
答案:3. (1) $x = 1$ (2) $x = 0$
解析:
(1) 解:展开方程左边得 $x^2 - 5x + 6 + 18$,右边得 $x^2 + 10x + 9$,即 $x^2 - 5x + 24 = x^2 + 10x + 9$,移项合并同类项得 $-15x = -15$,解得 $x = 1$。
(2) 解:展开方程左边得 $6x^2 - 10x - (6x^2 + 8x - 9x - 12) = 6x^2 - 10x - 6x^2 + x + 12 = -9x + 12$,右边得 $3x + 12$,即 $-9x + 12 = 3x + 12$,移项合并同类项得 $-12x = 0$,解得 $x = 0$。
(2) 解:展开方程左边得 $6x^2 - 10x - (6x^2 + 8x - 9x - 12) = 6x^2 - 10x - 6x^2 + x + 12 = -9x + 12$,右边得 $3x + 12$,即 $-9x + 12 = 3x + 12$,移项合并同类项得 $-12x = 0$,解得 $x = 0$。