The midpoint of a line segment joining two points \((x_1, y_1)\) and \((x_2, y_2)\) is given by the formula:
\(\text{Mid-point} = \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right)\)
Substitute the given points \((-1, 3)\) and \((8, 3)\):
\(\text{Mid-point} = \left( \frac{-1 + 8}{2}, \frac{3 + 3}{2} \right) = \left( \frac{7}{2}, \frac{6}{2} \right)\)
Simplify:
\(\text{Mid-point} = \left( \frac{7}{2}, 3 \right)\)
Thus, the correct answer is:
\(Option\space d)\ \left( \frac{7}{2}, \frac{9}{4} \right)\)