The triangle's side BC measures 28 units long.
We have an isosceles triangle from the diagram. This is due to the fact that the length of the sides of the base angles is equal.
As a result, we can say:
|AC| = |AB|
The angles are equal because the adjacent sides are equal.
Thus,
∠AC = ∠ AB
Now;
|AC| = |AB|
2x + 7 = 4x - 7
When we remove 2x from both sides, we get:
2x + 7 - 2x = 4x - 7 - 2x
7 = 2x - 7
2x = 7 + 7
2x = 14
x = 7
Line BC = 4x from the triangle's base
|BC| = 4(7)
|BC| equals 28 units
As a result, we can deduce that side BC is 28 units long.