Let a and b be two integers such that a^3 + ab^2 + b^3 = 0. (a) Prove algebraically that if a is even, b must also be even.
(b) Prove algebraically by contradiction that a cannot be odd

< coa = 150 ( given)

as ba and bc are tangents

so oc and oa is perpendicular to cb and ab respectively because in circle normal passes through centre

so in quadrilateral oabc

< coa + < oab + < ocb + < abc = 360

150 +90+90 + < abc = 360

330 + < abc = 360

< abc = 360 -330 = 30

so < abc = 30

⭐dhruv⭐

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