Respuesta :

Answer: 125

Step-by-step explanation:

The sum of all 3 interior angles of a triangle is 180.

18 + (12y + 5) + (4y - 3) = 180

20 + 16y = 180

Subtract 20 from both sides

16y = 160

Divide both sides by 16

y = 10

Now plug y back into equation for angle A

12y + 5

12(10) + 5

120 + 5 = 125

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