We can Notice that AB = AC
We know that if Two sides of a Triangle are Equal then Angles corresponding to those Sides are Equal.
⇒ ∠ABC = ∠ACB
⇒ (5x)° = 25°
⇒ x° = 5°
We know that Sum of Three Angles in a Triangle is equal to 180°
⇒ 25° + (5x)° + (3y + 70)° = 180°
⇒ 25° + 25° + (3y)° + 70° = 180°
⇒ (3y)° + 120° = 180°
⇒ (3y)° = 180° - 120°
⇒ (3y)° = 60°
⇒ y° = 20°