Respuesta :
She has two thirds of the marbles left after giving one third of them to John. The amount of marbles she has left is found from:
[tex]\frac{2}{3}(12a+21)=8a+14[/tex]
The answer is: 8a + 14 marbles.
[tex]\frac{2}{3}(12a+21)=8a+14[/tex]
The answer is: 8a + 14 marbles.