Respostas

2014-03-13T21:10:13-03:00
7x-(-2x+x)+(-3x+5x)  = 7x - (- x) + (2x) = 7x + x + 2x = 10x
2014-03-13T21:16:31-03:00
7x- (-2x +x)+(-3x+5x) 
7x + 2x - x - 3x + 5x 
14x - 4x = 10x