Answer:
x=11
Step-by-step explanation: since all the angles in the triangle equal 180, you take the angle you already have, 76, But because the sides are equal, the angle adjacent to the 76 is also 76. Now you add 76 and 76, 152, then you subtract that from 180, which is 28. You now take the 28 and put it equal to the 3x-5 and solve for x.