计算①4×(−3)2−13÷(−12)②[2-(-3)2]×[(-1)2006-(1-0.5×13)]③先化简3(x2-2xy)-[3x2-2y+2(xy+y)],再求当x=−12,y=−3时,代数式的值.④2-4(2-3x)=1-2(x-5)⑤x−35−x−43=1⑥0.5−0.2x0.2=0.1+x0.5
2019-05-07
计算
①4×(−3)2−13÷(−)
②[2-(-3)2]×[(-1)2006-(1-0.5×)]
③先化简3(x2-2xy)-[3x2-2y+2(xy+y)],再求当x=−,y=−3时,代数式的值.
④2-4(2-3x)=1-2(x-5)
⑤−=1
⑥=0.1+
优质解答
①4×(−3)2−13÷(−),
=36+26,
=62;
②[2-(-3)2]×[(-1)2006-(1-0.5×)],
=-7×,
=-;
③3(x2-2xy)-[3x2-2y+2(xy+y)]=-8xy,
当x=−,y=−3时,
原式=-12;
④去括号得:2-8+12x=1-2x+10,
移项合并得:14x=17,
系数化为1得:x=;
⑤去分母得:3x-9-5x+20=15,
移项合并得:2x=-4,
系数化为1得:x=-2;
⑥去分母得:25-10x=10+20x,
移项合并得:30x=15,
系数化为1得:x=.
①4×(−3)2−13÷(−),
=36+26,
=62;
②[2-(-3)2]×[(-1)2006-(1-0.5×)],
=-7×,
=-;
③3(x2-2xy)-[3x2-2y+2(xy+y)]=-8xy,
当x=−,y=−3时,
原式=-12;
④去括号得:2-8+12x=1-2x+10,
移项合并得:14x=17,
系数化为1得:x=;
⑤去分母得:3x-9-5x+20=15,
移项合并得:2x=-4,
系数化为1得:x=-2;
⑥去分母得:25-10x=10+20x,
移项合并得:30x=15,
系数化为1得:x=.