Answer:
16 yards by 14 yards
Explanation:
let w be the additional width from the walkway
The total area is then
(w + 10)(w + 8) = 224
Expand
w^2 + 18w + 80 = 224
Subtract 224 from both sides
w^2 + 18w - 144 = 0
Factor (if you can't see how this factors use the quadratic equation)
(w + 24)(w - 6) = 0
w = {-24, 6}
Disregard the -24 since width cannot be negative
w + 10 = 6 + 10 = 16
w + 8 = 6 + 8 = 14
The garden plus walkway is 16 yards by 14 yards