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1. 因式分解.
(1)(乌鲁木齐模拟)$x^2 - 4$ (4) (a-
(1)(乌鲁木齐模拟)$x^2 - 4$ (4) (a-
答案
(1) $(x+2)(x-2)$ (2) $x(x-1)$ (3) $3(x+y)(x-y)$ (4) $2a(a-3)^2$
2. 计算.
(1)(2026·新疆中考)$(a-1)^2 - a(a-2)$
(2)(2025·新疆中考)$a(1-a)+(a+1)(a-1)$
(3)(吐鲁番模拟)$x(x-7)-(x-3)(x+3)$
(4)
4. 若
(1)(2026·新疆中考)$(a-1)^2 - a(a-2)$
(2)(2025·新疆中考)$a(1-a)+(a+1)(a-1)$
(3)(吐鲁番模拟)$x(x-7)-(x-3)(x+3)$
(4)
4. 若
答案
(1) 1 (2) $a-1$ (3) $9-7x$ (4) $3a^2-12a+34$
3. 计算.
(1) $4(m+2)^2 - (m-1)(m+5)$
(2) $(x+1)(x-1) + x(x-2)$
(3) $(x+2y)^2 + (x-2y)(x+2y) + x(x-4y)$
(4) $(a^2b - 2ab^2 - b^3) ÷ b - (a - b)^2$
(1) $4(m+2)^2 - (m-1)(m+5)$
(2) $(x+1)(x-1) + x(x-2)$
(3) $(x+2y)^2 + (x-2y)(x+2y) + x(x-4y)$
(4) $(a^2b - 2ab^2 - b^3) ÷ b - (a - b)^2$
答案
(1) $3m^2+12m+21$ (2) $2x^2-2x-1$ (3) $3x^2$ (4) $-2b^2$
4.若$2a + b = -1$，求$4a^2 + 2ab - b$的值.
答案
4. 解:$\because 2a+b=-1,\therefore b=-1-2a,\therefore 原式=4a^2+2a(-1-2a)-(-1-2a)=4a^2-2a-4a^2+1+2a=1.$
