a)Since triangle ABC is isosceles with AB = BC, the base angles are congruent: ∠BAC = ∠BCA Sum of angles of a triangle = 180° (5x) + (5x) + 50 = 180 10x + 50 = 180 10x = 130 x = 13 b)Since line PBC is a straight line, the sum of angles along that line is 180° ∠PBQ + ∠QBA + ∠ABC = 180° Therefore: y + 3x + 50 = 180 Substituting 13 onto x y + 3(13)+50= 180 y + 39 +50 = 180 Y+ 89 =180 Y = 91