Respostas

2013-11-17T20:18:49-02:00
A = a-3B
A² = (a-3b)²
A² = a² -6ba + 3²b²
A² = a² -6ba + 9b²
2013-11-17T20:19:47-02:00
(a-3b).(a-3b)= A^2 -3AB-3AB+9B^2

A^2-6AB+9B^2