Answer:
y = 5
Explanation:
The base angles of this isosceles triangle are congruent, so the angle at A is ...
A = 180° -2(75°) = 30°
(4y +10)° = 30° . . . . . substitute the given expression for angle A
4y = 20 . . . . . . . . . . divide by °, subtract 10
y = 5 . . . . . . . . . divide by 4
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Additional comment
The value of x is 25.
x is found from 3x=75, by dividing both sides of this equation by 3.