Answer:
17 units
Step-by-step explanation:
Because the triangle is isosceles, 2 of its sides are congruent; namely, the two sides that are opposite of the 2 congruent angles are contruent.
Because of the reason stated above, we can see that AC is congruent to BC, meaning that:
x+9=2x-8
-x -x
9=x-8
+8 +8
17 = x
Notice that BC is equal to x, so 17 is our final answer.
