-7,-5,-3,-1,0,1,3,5,7 `' U. O/ v% t$ ^ Y) THow many distinct products can be obtained by multiplying any two numbers in the list of numbers above? 3 p8 \* U o& S; n" S y(A)9 (B)17 (C)19 (D)21 (E)31 0 v; r/ @$ J/ }) l答案是B 想不通啊 哪位牛人请解答此题 并说明过程9 i2 p+ w& k/ X3 l/ o- O7 w- R2 r
' U: b e) l1 w4 dIt has been argued that politics as_____,whatever its transcendental claims,has always been the systematic organization of common hatreds0 ]9 t7 E" J! K8 X
(A)a theory (B)an ideal (C)a practice (D) a contest (E)an enigma 2 i6 m: _, s( T答案是C 为什么啊??有什么逻辑信号词吗??
on the math problem you can do 9 nCr 2 ( aka 9 pick (permutation) 2) then since all of the number repeat twice divide 2 again and because of the zero factor you have to minues one. So it looks like this 9!/(2!*7!)/2-1.