By using variables $x$ and $y$, form any five linear equations in two variables.

Write five solutions of the equation $x+y=7$.

Solve the following sets of simultaneous equations.

$x + y = 4; 2x - 5y = 1$

Solve the following sets of simultaneous equation.

$2x+y=5; 3x-y=5$

Solve the following sets of simultaneous equations.

$3x-5y=16 ; x-3y=8$

Solve the following sets of simultaneous equations.

$2y-x=0 ; 10x+15y=105$

Solve the following sets of simultaneous equations.

$2x+3y+4=0 ; x-5y=11$

Solve the following sets of simultaneous equations.

$2x-7y=7 ; 3x+y=22$

In an envelope there are some $₹5$ notes and some $₹10$ notes. Total amount of these notes together is $₹350$. Number of $₹5$ notes are less by $10$ than number of $₹10$ notes. Then find the number of $₹5$ and $₹10$ notes.