Answer:
The length of BC is, 17 units
Step-by-step explanation:
Isosceles Triangle states that :
a triangle has two sides of equal length and has equal base angle.
From the given figure, we have
or we can say that angle C is equal to the angle B.
then, by the definition of Isosceles triangle,
AC = AB

Add 8 both sides of an equation:

Simplify;
x+17 =2x
Subtract x from both sides of an equation:
x+17-x=2x-x
Simplify:
17 units = x
Therefore, the length of BC = x unit = 17 units