(1)化简: x + 1 x - 1 - 4 x x 2 - 1
(2)解不等式组 x + 1 2 ⩽ 1 5 x - 8 < 9 x ,并写出它的整数解.
计算与化简:(第(1)(2)(3)题每题4分,第(4)题6分,共18分) (1) 计算:-2×(-3)+(-48)÷6; (2)计算: (3)化简:; (4)先化简,再求值:其中a=2,b=-1
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x-2=x(x-2)