Question:
Write the number of solutions of the following pair of linear equations:
$x+3 y-4=0$
$2 x+6 y=7$
Solution:
The given linear pair of equations are
$x+3 y-4=0$
$2 x+6 y=7$
$a_{1}=1, a_{2}=2, b_{1}=3, b_{2}=6, c_{1}=4, c_{2}=7$
$\frac{a_{1}}{a_{2}}=\frac{1}{2}$
$\frac{b_{1}}{b_{2}}=\frac{3}{6}$
$\frac{b_{1}}{b}=\frac{1}{2}$
$\frac{c_{1}}{c_{2}}=\frac{4}{7}$
If $\frac{a_{1}}{a_{2}}=\frac{b_{1}}{b_{2}} \neq \frac{c_{1}}{c_{2}}$ then
$a_{1} b_{2}=a_{2} b_{1}$
$a_{1} b_{3}-a_{2} b_{1}=0$
$1 \times 6-2 \times 3=0$
$6-6=0$
Hence, the number of solutions of the pair of linear equation is 0 .
Therefore, the equations have no solution.