Respostas

2013-11-29T10:34:34-02:00
2x²-xy
2.-2²-(-2.4)
2.(-2²)-(-2.4)
2.4-(-8)
8+8
16

Portanto letra a) 16.
1 3 1
2013-11-29T10:54:07-02:00
2 . ( - 2 ) ² - ( - 2 ) . 4 =
2 . 4 - ( - 8 )  =
8 + 8 = 16