Find the value of $k$ if $(5,2)$ is a solution of $3 x+k y=25$

Write each of the following as an equation in two varlables

$5 y=3$

Draw the graphs of linear equations $y=x$ and $y=-x$ on the same cartesian plane.

What do you observe?

Write four solutions for each of the following equations

$2 x+3 y=7$

Express the following linear equation in the form $a x+b y+c=0$ and indicate the values of $a, b$ and $c$ in each case

$\pi x-3 y=18$