Question

14/x+3/y=5 21/x-8/y=-5 by substitution

Answer 1

Eq.(i)

$\frac{14}{x} +\frac{3}{y} =5\\\\\frac{21}{x} -\frac{8}{y} =-5$

Eq.(ii)

In (i)

$\frac{14}{x}=5-\frac{3}{y}$

$\frac{14}{x} =\frac{5y-3}{y}$

$x=\frac{14y}{5y-3}$------------------------(iii)

putting value of 'x' from Eq. (iii)in Eq.(ii):

$21/\frac{14y}{5y-3} -\frac{8}{y} = -5$

$21*\frac{5y-3}{14y} -\frac{8}{y} =-5\\\\\frac{105y-63}{14y} -\frac{8}{y} =-5\\\\\frac{105y-63-112y}{14y} =-5$

$-63-7y=-70y\\-63=-63y\\So, y=1$

Now, putting the value of y in (iii):

$x=\frac{14y}{5y-3} =\frac{14*1}{(5*1)-3}$

$x=\frac{14}{2} \\x=7$

So, y=1

and x=7