Question

The pair of linear equations $x+2y=5,7x+3y=13$ has a unique solution

• A. $x=1,y=2$
• B. $x=2,y=1$
• C. $x=3,y=1$
• D. $x=1,y=3$

Answer 1

Answer: (A)

$x=1,y=2$

Given equations are:
$x+2y=5$ ....(1)
$7x+3y=13$ .....(2)
Multiplying equation (1) by 7
$7x+14y=35$ .....(3)
Subtracting equation (2) from equation (3), we have
$11y=22$
$y=2$
Now putting $y$ value in equation (1)
$\Rightarrow x+2\left(2\right)=5$
$\Rightarrow x=5-4$
$\Rightarrow x=1$
$x=1,y=2$