Write an equation of a line passing through the point representing the solution of the pair of linear equations $x+y=2$ and $2x-y=1$. How many such lines can we find?

(D) First,we solve the pair of linear equations:
$x + y = 2$ --- $(i)$
$2x - y = 1$ --- $(ii)$
Adding equations $(i)$ and $(ii)$,we get:
$(x + y) + (2x - y) = 2 + 1$
$3x = 3$
$x = 1$
Substituting $x = 1$ in equation $(i)$:
$1 + y = 2$
$y = 1$
The solution point is $(1, 1)$.
Any line passing through $(1, 1)$ can be written in the form $y - 1 = m(x - 1)$,where $m$ is the slope. For example,if $m = 1$,the equation is $y - 1 = x - 1$,which simplifies to $y = x$.
Since there are infinitely many possible values for the slope $m$,there are infinitely many such lines that can pass through the point $(1, 1)$.