Lines coincide (infinitely many solutions) if

Lines coincide (infinitely many solutions) if
  1. $\dfrac{a_1}{a_2} = \dfrac{b_1}{b_2} = \dfrac{c_1}{c_2}$
  2. $\dfrac{a_1}{a_2} \ne \dfrac{b_1}{b_2}$
  3. $\dfrac{a_1}{a_2} = \dfrac{b_1}{b_2} \ne \dfrac{c_1}{c_2}$
  4. $a_1 b_2 = a_2 b_1$

Solution

All ratios equal $\Rightarrow$ same line.

Asked in: MH-SSC-9

Practice more Linear Equations in Two Variables questions on Aicharya