Divide the total cost by all 5 panes to get the cost of 1 pane:
14.25/5 = 2.85
Then multiply by 2:
2.85 * 2 = $5.7
Add 14 to each side to undo the negative 14/negative sign. divide each side by 6 to undo the 6x, simplify=5
Each box may receive more than one letter.