Use the following graph and answer the given questions :
(a) Write the co-ordinates of points A, B and C.
(b) Find the equation of a line passing through the mid-point of AC and parallel to AB.

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(a) From graph,
Coordinates of :
A(4, 8), B(-1, 2), C(6, 2)
Hence, A(4, 8), B(-1, 2), C(6, 2).
(b) Midpoint of AC,
By formula,
Midpoint = $\Big(\frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2}\Big)$
Substituting values, we get :
Mid-point of AC = $\Big(\frac{4 + 6}{2}, \frac{8 + 2}{2}\Big)$ = (5, 5).
By formula,
Slope = $\frac{y_2 - y_1}{x_2 - x_1}$
Thus,
Slope of AB = $\frac{8 - 2}{4 - (-1)}$
= $\frac{6}{5}$.
Since, slope of parallel lines are equal, thus slope of required line (m) = $\frac{6}{5}$.
By point-slope form,
Equation : y - y1 = m(x - x1)
Equation of line parallel to AB and passing through mid-point of AC is given by,
⇒ y - 5 = $\frac{6}{5}(x - 5)$
⇒ 5(y - 5) = 6(x - 5)
⇒ 5y - 25 = 6x - 30
⇒ 5y - 25 + 30 = 6x - 30
⇒ 5y - 5 = 6x
⇒ 6x - 5y - 5 = 0.
Hence, equation of required line = 6x - 5y - 5 = 0.