Verbseoul.
하다 verb (adj)
유익하다yuikhadato be profitable

To say to be profitable politely in the present tense, use 유익해요 (yoo-ee-kae-yoh). Below is the full conjugation of 유익하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
유익해
yoo-ee-kae
유익해요
yoo-ee-kae-yoh
유익합니다
yoo-ee-kahm-nee-dah
Past
유익했어
yoo-ee-kae-ssuh
유익했어요
yoo-ee-kae-ssuh-yoh
유익했습니다
yoo-ee-kae-sseum-nee-dah
Future
유익할 거야
yoo-ee-kahl- -guh-yah
유익할 거예요
yoo-ee-kahl- -guh-yae-yoh
유익할 겁니다
yoo-ee-kahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
유익하세요
yoo-ee-kah-sae-yoh
Suggestion / Let's Polite (요)
유익해요
yoo-ee-kae-yoh
Question Polite (요)
유익해요?
yoo-ee-kae-yoh-?
Connective “and” — (고)
유익하고
yoo-ee-kah-goh
Conditional “if” — (면)
유익하면
yoo-ee-kah-myuhn
Noun form — (기)
유익함
yoo-ee-kahm