If all angles have the same measure, then this is an equilateral triangle.
Therefore we have the equation:
4x - 30 = 3x - 5 add 30 to both sides
4x = 3x + 25 subtract 3x from both sides
x = 25
Check:
|AB| = 3x - 5 → |AB| = 3(25) - 5 = 75 - 5 = 70
|BC| = 2x + 20 → |BC| = 2(25) + 20 = 50 + 20 = 70
|AC| = 4x - 30 → |AC| = 4(25) - 30 = 100 - 30 = 70
CORRECT :)
Answer: x = 25