Respostas

2014-06-26T22:16:07-03:00
A) A+B+C
2x²-8x-7+x²-5x+7+2x-9
3x²-5x-16

B) A-B-C
(2x²-8x-7)-(x²-5x+7)-(2x-9)
2x²-8x-7-x²+5x-7-2x+9
x²-5x-5

C) -5B
-5*(x²-5x+7)
-5x²+25x-35
4 2 4