Write the following as an equation in two variables:
$4y = 24$

Express the following linear equation in the form $ax + by + c = 0$ and indicate the values of $a, b$ and $c$ in each case:
$x = \frac{2}{5}y + 10$

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 Rs. $x$ and that of a pen to be Rs. $y$).

Write the following as an equation in two variables:
$2x = 9$

Express the linear equation $3x + 2 = 0$ in the form $ax + by + c = 0$ and indicate the values of $a$,$b$,and $c$.

Yamini and Fatima,two students of Class $IX$ of a school,together contributed Rs. $100$ towards the Prime Minister's Relief Fund to help the earthquake victims. Write a linear equation which satisfies this data. (You may take their contributions as Rs. $x$ and Rs. $y$.) Draw the graph of the same.