For this case we must find the quotient of [tex]21a^3-14a[/tex] between -7:
That is to say:
[tex]\frac {21a ^ 3-14a} {- 7} =\\\frac {21a ^ 3} {- 7} + \frac {-14a} {- 7}[/tex]
We know that:
[tex]\frac {21} {7} = 3\\\frac {14} {7} = 2\\\frac {+} {-} = -[/tex]
Finally:
[tex]-3a ^ 3 + (2a) =\\-3a ^ 3 + 2a[/tex]
Answer:
[tex]-3a ^ 3 + 2a[/tex]
Option A