计算 ( 2019 - π ) 0 - 2 sin 30 ° + 12 + ( - 1 2 ) - 3 .
解不等式组: x - 1 ⩽ 4 3 x - 2 ( 2 - x ) > 6 .
计算: 8 + | - 2 | - 2 sin 45 ° - ( 2018 - 1 ) 0 .
解分式方程: 2 x x - 1 = x 2 x - 2 + 1
计算: ( 3 - 1 ) 0 + | - 1 2 | - ( 1 3 ) - 1 + 3 cos 30 °