Respostas

2013-08-21T23:00:38-03:00
5x²{ x² -[2x²+(x² +2x²) +10x²]}
5x²{x² -[2x² +(3x²) +10x²]}
5x²{x² -[ 2x² +3x² +10x²]}
5x²{ x²-[15x²]}
5x² {x² -15x²}
5x²{-14x²]
5x² -14x² = -9x²