Respostas

2013-09-05T15:28:36-03:00
4(x+5) +3(x+5) = 21
4x + 4*5 + 3x + 3*5 = 21
4x + 3x + 20+ 15 = 21
7x + 35 = 21
7x = 21 - 35
7x = -14
x = -14/7
x = -2
4 4 4