计算:(1)?14?(1?0.5)×13×[2?(?3)2];(2)90°-(23°16′+17°23′)+19°40′÷6;(3)?22÷45×

计算:(1)?14?(1?0.5)×13×[2?(?3)2];(2)90°-(23°16′+17°23′)+19°40′÷6;(3)?22÷45×(34?45);(4)(x3-2y3-3x2y)-(3x3-3y3-7x2y).

(1)原式=-1-0.5×
1
3
×(-7)
=-1+
7
6

=
1
6

(2)原式=90°-40°39′+3°16′40″
=93°16′40″-40°39′
=52°37′40″;
(3)原式=-4×
5
4
×(-
1
20
)=
1
4

(4)原式=x3-2y3-3x2y-3x3+3y3+7x2y
=(1-3)x3+(-2+3)y3+(-3+7)x2y
=-2x3+y3+4x2y.
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