Use the method of elimination to find the solution of the following pair of linear equations: $0.4 x + 0.3 y = 1.7, 0.7 x - 0.2 y = 0.8$

Form the pair of linear equations in the following problems,and find their solutions (if they exist) by the elimination method:
Five years ago,Nuri was thrice as old as Sonu. Ten years later,Nuri will be twice as old as Sonu. How old are Nuri and Sonu?

Aruna has only $Rs. 1$ and $Rs. 2$ coins with her. If the total number of coins that she has is $50$ and the amount of money with her is $Rs. 75$,then the number of $Rs. 1$ and $Rs. 2$ coins are,respectively

Solve the following pair of linear equations by the method of elimination:
$5x - 3y = 1$
$2x + 5y = 19$

Solve the following pairs of equations by the method of elimination:
$x + 3y - 6 = 0$
$2x - y = 5$

Solve the following pairs of linear equations: $\frac{2}{x} + \frac{3}{y} = \frac{9}{xy}, \quad \frac{4}{x} + \frac{9}{y} = \frac{21}{xy} \quad (x \neq 0, y \neq 0)$