Question

Consider the two lines describer the equations Ax + By = C and Dx + Ey = F

a) What must be true for these two lines to parallel?

b) What must be true in order for these two lines to be perpendicular?

c) What must be true in order for these two lines to be identical?

Answer 1

a).

A must be equal to D i.e gradients must be equal.

b).

The product of A and B must be equal to -1

c).

A, B and C must be equal to D, E and F respectively.