Question

The pair of equations5x+2y+7=0 and 10x+4y+9=0 has how many solutions ​

Answer 1

5x+2y+7 = 0

10x + 4y+ 9 = 0

$\frac{a_{1} }{a_{2} } = \frac{5}{10} = \frac{1}{2} \\\\\frac{b_{1} }{b_{2} } = \frac{2}{4} = \frac{1}{2} \\\\\\\frac{c_{1} }{c_{2} } = \frac{7}{9}$

$\frac{a_{1} }{a_{2}} = \frac{b_{1}}{b_{2}} \neq \frac{c_{1}}{c_{2}}$

So there will be no solutions.