问题
解答题
(1)计算:-32-5×|-3|+(-2)2÷4 (2)2-
(3)化简并求值:4(x-1)-2(x2+1)-
(4)解不等式:
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答案
(1)原式=-9-15+1
=-24+1
=-23;
(2)去分母得,12-2(2x-4)=-(x-7),
去括号得,12-4x+8=-x+7,
移项得,-4x+x=7-12-8,
合并同类项得,-3x=13,
系数化为1得,x=-
;13 3
(3)原式=4x-4-2x2-2-2x2+x
=-4x2+5x-6,
当x=3时,原式=(-4)×9+5×3-6=-27;
(4)去分母得,3(3+x)-6≤4x+3,
去括号得,9+3x-6≤4x+3,
移项得,3x-4x≤3+6-9,
合并同类项得,-x≤0,
系数化为1得,x≥0.