If the graph of the equation $3x + ay = 7$ passes through the point $(3, -1)$,then the value of $a$ is:

Give the equations of two lines passing through $(2, 14)$. How many more such lines are there,and why?

The total cost of a school picnic consists of two parts: a fixed bus fare of ₹ $200$ and the cost of snacks at the rate of ₹ $30$ per student. Representing the total number of students by $x$ and the total cost by $y$,form a linear equation in two variables. If the number of students going on the picnic is $40$,find the total cost.

Write four solutions for the equation: $2x + y = 7$

State whether the following statement is true or false:
The graph of the equation $3x = 4y$ is a line passing through the origin.

How many linear equations in $x$ and $y$ can be satisfied by $x = 1$ and $y = 2$?