w= woman's age
g= grandson's age
CURRENTLY
The woman's age (w) equals five times that of her grandson's age (g).
w= 5 * g
w= 5g
FUTURE
The woman's age (w) equals four times that of her grandson's age (g) plus the twelve years.
w= 4g + 12
ANSWER: A linear system that models this situation is w= 4g + 12.
Hope this helps! :)