Question

Solve the following pair of linear equations in two variables:
$3=2x+y$ and $9=4x-y$

Answer 1

Given:-

$3=2x+y.....\left(1\right)$

$9=4x-y.....\left(2\right)$

Adding equation $\left(1\right)\&\left(2\right)$, we have

$3+9=(2x+y)+(4x-y)$

$12=6x$

$\Rightarrow x=\frac{12}{6}=2$

Substituting the value of $x$ in equation $\left(1\right)$, we have

$3=2\times 2+y$

$\Rightarrow y=3-4=-1$

Hence the value of $x$ and $y$ are $2$ and $-1$ respectively.