—5 | 5 — 1| — 10 = - 50

The answer is -30 not -50

Step-by-step explanation:

−5(|5−1|)−10

=−5(|4|)−10

=(−5)(4)−10

=−20−10

=−30

< 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⭐