In the triangle ABC, if (a + B + C) (a + C-B) = 3aC, then B =?

60°
Brackets open A2 + C2 + 2ac-b2 = 3aC
If A2 + c2-b2 = AC, then CoSb = A2 + c2-b2 / 2Ac = 1 / 2, then B = 60 degree

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