Answer and Explanation:
The journal entries are shown below:
On July 1
Treasury stock Dr (670 shares × $9 per share) $6,030
To Cash $6,030
(Being the purchase of treasury stock is recorded)
For recording this we debited the treasury stock as it increased the treasury and credited the cash as it decreased the assets
On Sep 1
Cash Dr (420 shares × $14 per share) $5,880
To Treasury Stock (420 shares × $9 per share) $3,780
To Additional paid in capital - Treasury stock $2,100
(Being the resale of treasury stock is recorded)
For recording this we debited the cash as it increased the assets and credited the treasury stock and additional paid in capital as the sale is made