计算: ( 1 2 ) - 1 - ( π - 1 ) 0 + | 1 - 3 | .
又PE⊥CB于E,若BC=10,且CE∶EB=3∶2,求AB的长.
197×203
( 998 ) 2
a - b 2 - a a - 2 b
( 9 x 4 - 15 x 2 + 6 x ) ÷ 3 x