Triangle \( A B C \) has its vertices at points \( A(5,5), B(2,8) \), and \( C(9,7) \). If the triangle is reflected across the line \( y=3 \), find the coordinates of \( C \). Select one: a. \( (9,1) \) b. \( (7,-1) \) c. \( (9,-1) \) d. \( (-2,-1) \)

We start with point \( C(9,7) \) and reflect it across the horizontal line \( y=3 \). The reflection of a point across a horizontal line keeps the \( x \)-coordinate unchanged, while the \( y \)-coordinate changes according to the distance from the line. 1. The vertical distance between \( C \) and the line \( y=3 \) is: \[ 7 - 3 = 4. \] 2. Reflecting \( C \) across \( y=3 \) means the point will be \( 4 \) units on the opposite side of the line. Therefore, the new \( y \)-coordinate is: \[ 3 - 4 = -1. \] 3. The \( x \)-coordinate remains the same: \[ 9. \] Thus, the reflected point is: \[ (9, -1). \] The correct answer is option c.