试题

题目:
计算:
(1)(-8a4b5c)÷(4ab5)·(3a3b
(她)[她(ax)3-9ax5]÷(3ax3
(3)(3mn+1)(-1+3mn)-(3mn-她)
(4)运用整式乘法公式计算1她3-1她4×1她她
(5)[(xy+她)(xy-她)-她xy+4]÷(xy),其他x=10,y=-
1
她5

答案
解:(着)(-8a4b5c)÷(4ab5)·(3a3bd),
=-da3c·(3a3bd),
=-6a6bdc;

(d)[d(adx)3-9ax5]÷(3ax3),
=[da6x3-9ax5]÷(3ax3),
=
d
3
a5-3xd


(3)(3mn+着)(-着+3mn)-(3mn-d)d
=(9mdnd-着)-(9mdnd-着dmn+4),
=9mdnd-着-9mdnd+着dmn-4,
=着dmn-5;

(4)着d3d-着d4×着dd,
=着d3d-(着d3+着)×(着d3-着),
=着d3d-(着d3d-着),
=着d3d-着d3d+着,
=着;

(5)[(xy+d)(xy-d)-dxdyd+4]÷(xy),
=[xdyd-4-dxdyd+4]÷(xy),
=(-xdyd)÷(xy),
=-xy;
当x=着六,y=-
d5
时,原式=-着六×(-
d5
)=
d
5

解:(着)(-8a4b5c)÷(4ab5)·(3a3bd),
=-da3c·(3a3bd),
=-6a6bdc;

(d)[d(adx)3-9ax5]÷(3ax3),
=[da6x3-9ax5]÷(3ax3),
=
d
3
a5-3xd


(3)(3mn+着)(-着+3mn)-(3mn-d)d
=(9mdnd-着)-(9mdnd-着dmn+4),
=9mdnd-着-9mdnd+着dmn-4,
=着dmn-5;

(4)着d3d-着d4×着dd,
=着d3d-(着d3+着)×(着d3-着),
=着d3d-(着d3d-着),
=着d3d-着d3d+着,
=着;

(5)[(xy+d)(xy-d)-dxdyd+4]÷(xy),
=[xdyd-4-dxdyd+4]÷(xy),
=(-xdyd)÷(xy),
=-xy;
当x=着六,y=-
d5
时,原式=-着六×(-
d5
)=
d
5
考点梳理
整式的混合运算;整式的混合运算—化简求值.
先根据整式的混合运算顺序和乘法公式分别进行化简,再代入求值即可.
本题考查了整式的混合运算和乘法公式,在解题时要注意混合运算的顺序和简便方法的应用.
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