Question

3a² - b² (para a = -2 e b = -7) ?

Answer 1

3 (-2)^2 - (-7)^2
3.4 - 49
12-49= -37

Answer 2

3a²-b²
3•a²-b²
3•(-2)²-(-7)²
3•4-(49)
12-49
-37