The cost of a notebook is twice the cost of a pen. Write a linear equation in two variables to represent this statement.

(Take the cost of a notebook to be $\rm {Rs.}$ $x$ and that of a pen to be $\rm {Rs.}$ $y$).

Express the following linear equations in the form $ax + by + c = 0$ and indicate the values of $a$, $b$ and $c$ in each case : $x=3 y$

You know that the force applied on a body is directly proportional to the acceleration produced in the body. Write an equation to express this situation and plot the graph of the equation.

Write each of the following as an equation in two variables :

$(i)$ $x=-\,5$

$(ii)$ $y=2$

$(iii)$ $2x=3$

$(iv)$ $5y=2$

Draw the graph and linear equations in two variables : $y=3 x$

Write each of the following equations in the form $ax + by + c = 0$ and indicate the values of $a$, $b$ and $c$ in each case :

$(i)$ $2 x+3 y=4.37$

$(ii)$ $x-4=\sqrt{3} y$

$(iii)$ $4=5 x-3 y$

$(iv)$ $2 x=y$