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1. 计算:
(1)$(-8)-(+14)+(-6)-(-11)$;
(2)$-24×2 \dfrac{1}{4}+(-4 \dfrac{1}{2})×\dfrac{2}{9}$;
(3)$\dfrac{3}{8}×\dfrac{8}{9}÷(\dfrac{3}{4}-\dfrac{5}{6})$;
(4)$(-8)+(-4)-(-3)^2×(-1 \dfrac{2}{3})$;
(5)$3.5×(-5)+3^2-3÷\dfrac{1}{2}$;
(6)$(-\dfrac{3}{4}+\dfrac{7}{12}-\dfrac{5}{9})÷(-\dfrac{1}{36})$.
(1)$(-8)-(+14)+(-6)-(-11)$;
(2)$-24×2 \dfrac{1}{4}+(-4 \dfrac{1}{2})×\dfrac{2}{9}$;
(3)$\dfrac{3}{8}×\dfrac{8}{9}÷(\dfrac{3}{4}-\dfrac{5}{6})$;
(4)$(-8)+(-4)-(-3)^2×(-1 \dfrac{2}{3})$;
(5)$3.5×(-5)+3^2-3÷\dfrac{1}{2}$;
(6)$(-\dfrac{3}{4}+\dfrac{7}{12}-\dfrac{5}{9})÷(-\dfrac{1}{36})$.
答案
1. (1)-17 (2)-55 (3)-4 (4)3 (5)-14.5 (6)26
2. 化简:
(1)$2x - 5y + 3 - 3x + y$;
(2)$\frac{1}{3}(9x - 3) + 2(x + 1)$;
(3)$2(2a - 3b) - 3(2b - 3a)$;
(4)$3x^2y - 4xy^2 - 3 + 5x^2y + 2xy^2 + 5$.
(1)$2x - 5y + 3 - 3x + y$;
(2)$\frac{1}{3}(9x - 3) + 2(x + 1)$;
(3)$2(2a - 3b) - 3(2b - 3a)$;
(4)$3x^2y - 4xy^2 - 3 + 5x^2y + 2xy^2 + 5$.
答案
2. (1)$-x-4y+3$ (2)$5x+1$ (3)$13a-12b$ (4)$8x^2y-2xy^2+2$
3. 已知$(x+1)^2 + |y-1| = 0$，求$2(xy - 5xy^2) - (3xy^2 - xy)$的值.
答案
3. 由题意得,$x+1=0,y-1=0$,解得$x=-1,y=1$,
原式=$3xy-13xy^2=3×(-1)×1-13×(-1)×1=10$.
原式=$3xy-13xy^2=3×(-1)×1-13×(-1)×1=10$.
