The point of the form $(a, -a)$ always lies on the line

"The price of a bat in a toy store is five times the price of a ball." Represent this statement as a linear equation in two variables.

Express the following linear equation in the form $ax + by + c = 0$ and indicate the values of $a, b$ and $c$ in each case:
$3x = 2y + 1.\overline{5}$

State whether the following statement is true or false:
If $(5, -2)$ is a solution of $5x + 2y = k$,then $k = 0$.

The equation $x=7$,in two variables,can be written as

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.