Perhaps you should try some spelling variations:
"poly equation" » "pole equation", "golay equation", "pol's equation", "poley equation", "polly equation"
"pool equation" » "pell equation", "pol equations", "pool evaluation"
"pol equation" » "pole equation", "poll equation"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("pol equation") OR ("pool equation"))) OR ("poly equation")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"pol equation\") OR (\"pool equation\"))) or (\"poly equation\"))".
• Removing quotes may allow a broader search: (((( pol equation ) OR ( pool equation ))) or ( poly equation )).
• Adding a wildcard symbol may retrieve word variants: (((("pol equation") OR ("pool equation"))) or ("poly equation"))*.