Please solve question 16

Please solve question 16 ACE Bev N. if the b 1

Since AB = BC triangle ABC is an isoceles triangle and <ABC = <ACB = x
Since DB = DC triangle DBC is an isoceles triangle and <DBC = <DCB = y

in first figure
<ABD = <ABC + <DBC = x +y
<ACD = < ACB + <DCB = x + y
thus <ABD = <ACD

in second figure
<ABD = <ABC - <DBC = x - y
<ACD = < ACB - <DCB = x - y
thus <ABD = <ACD
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