What is the length of BC¯¯¯¯¯ ?

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Triangle A B C with horizontal side B C. Vertex A lies above side B C. Angle B and angle C are marked congruent. The length of side A C is labeled as x plus 9. The length of side A B is labeled as 2 x minus 8. The length of side B C is labeled as x.

The length of BC is 17

Step-by-step explanation:

When we construct a triangle with the data, we will end up a  isosceles triangle.

In a isosceles triangle , we know that tow angles and two sides are equal

The questions states that

Then sides  AC  and AB  are also equal

On equation their values

2X - 8 =  X+9

2X = X + 9 +8

2X = X + 17

2X - X = 17

X =  17

The length of BC = X =  17