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y = 4

Step-by-step explanation:

In this situation, because all the angles have the same arc mark, they must have the same measure which means that the triangle is equiangular. Therefore, you can use the definition of an equilateral triangle which states that if the triangle is equiangular, it must be equilateral which means that all sides are the same. This is because x + x + x = 180 → 3x = 180 → x = 60. When you learn trigonometry, you will realize that the proportion of sides corresponds to the angles. Or you could experiment and you may realise that if the angles of the triangles are all 60° then you can only form a triangle where the sides are all equal. If all sides are the same, then 9y - 3 = 7y + 5

So if 9y - 3 = 7y + 5, then

9y - 3 = 7y + 5 →

[subtract 7y from both sides]

9y - 7y - 3 = 7y - 7y + 5 →

2y - 3 = 5 →

[add 3 to both sides]

2y - 3 + 3 → 5 + 3 → 2y = 8 →

[divide both sides by 2]

y = 4

a

step-by-step explanation: