(1)解方程: x x + 2 = 2 x − 1 + 1 .
(2)解不等式组: 2 x − 4 > 0 x + 1 ⩽ 4 ( x − 2 )
计算:
(本题6分) (1)已知:sinα·cos60º=,求锐角α; (2)计算:.
(1)(配方法) (2) (3)(4)()()—
计算:.
(每小题5分,本题共20分)计算: (1)(2)(-+-)×(-48) (3)(4)