Will give brainliest

what is the value of y?

Δ ABC is an isosceles triangle in which the two base angles are equal.  A such 3x = 75°.

Now, since the sum of the angles in a triangle is 180°,
 then (4y + 10)° + 75° + 3x = (4y + 10 + 75 + 75)° = 180°
⇒   (4y + 10 + 75 + 75)° = 180°
                           4y = 180° - 160°
                             y = 5°

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