解:(1)50°24′×3-98°12′25″,
=150°72′-98°12′25″,
=151°12″-98°12′25″,
=52°59′35″;
(2)
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,
=30÷(
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-
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)-1÷
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×10,
=30÷
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-1÷
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×10,
=900-100,
=800;
(3)(-2)
3+(-3)×[(-4)
2+2]-(-3)
2÷(-2),
=(-2)
3+(-3)×18-(-3)
2÷(-2),
=-8+(-3)×18-9÷(-2),
=-8-54+
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,
=-57
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;
(4)1-2(1-2x+x
2)+3(-x
2+x-1),
=1-2+4x-2x
2-3x
2+3x-3,
=-5x
2+7x-4;
(5)2(x-2)-3(4x-1)=5(1-x),
去括號(hào),得
2x-4-12x+3=5-5x,
移項(xiàng),合并同類(lèi)項(xiàng),得
-5x=6,
系數(shù)化為1,得
x=-
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.
(6)
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-1,
去分母,得
3(3x+5)=2(2x-1)-6,
去括號(hào),得
9x+15=4x-2-6,
移項(xiàng),合并同類(lèi)項(xiàng),得
5x=-23,
系數(shù)化為1,得
x=-
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.
分析:(1)將50°,24′分別與3相乘,然后按照進(jìn)率將分化為度,然后與98°12′25″相減,即可得出答案;
(2)按照有理數(shù)混合運(yùn)算法則進(jìn)行運(yùn)算,即可直接求得答案;
(3)按照有理數(shù)混合運(yùn)算法則進(jìn)行運(yùn)算,即可直接求得答案;
(4)按照整式加減運(yùn)算法則進(jìn)行運(yùn)算,然后合并同類(lèi)項(xiàng),即可直接求得答案;
(5)將方程去括號(hào),然后移項(xiàng),合并同類(lèi)項(xiàng),再將系數(shù)化為1,即可求解;
(6)將方程去分母,去括號(hào),然后移項(xiàng),合并同類(lèi)項(xiàng),再將系數(shù)化為1,即可求解.
點(diǎn)評(píng):此題主要考查學(xué)生對(duì)解一元一次方程,整式的加減,有理數(shù)的混合運(yùn)算,度分秒的換算等知識(shí)點(diǎn)的理解和掌握,此題難度不大,但涉及到的知識(shí)點(diǎn)較多,非常繁瑣,答題時(shí)需要認(rèn)真細(xì)心.