In the following expression, n is a rational number: which expression below is equivalent to this expression? a.-n(-0.7+(-0.7)) b.0.7n+0.7n c.-0.7n - 0.7n d.-0.7 * n +(-0.7)*(-n)

< 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⭐