Find the equation of the chord of contact of tangents from the point $\left(-3,1\right)$ to the parabola $y^2 = 8x$.
Equation of parabola is $\;$ $y^2 = 8x$
Comparing with the standard equation of parabola $\;$ $y^2 = 4ax$ $\;$ gives
$4a = 8 \implies a = 2$
Equation of the chord of contact of tangents from the point $\left(x_1, y_1\right)$ to the parabola $y^2 = 4ax$ is
$yy_1 = 2a \left(x + x_1\right)$
Here, $\left(x_1, y_1\right) = \left(-3,1\right)$
$\therefore$ $\;$ Required equation is
$1 \times y = 2 \times 2 \times \left(x - 3\right)$
i.e. $\;$ $4x - y - 12 = 0$