Answer :
[tex]-5x+3y = 10~~~~ .....(i)\\\\2x+5y =-35~~~ ....(ii)\\\\\text{Multiply equation (ii) by}~ \dfrac 35~ \text{ and do (ii) -(i)}\\\\\\\dfrac 35(2x+5y) - (-5x+3y) = \dfrac 35}(-35) - 10\\\\\implies \dfrac{6x}5 +3y + 5x -3y = -21-10 = -31\\\\\implies \dfrac{6x + 25x}5 = -31\\\\\implies 31x = -31 \times 5\\\\\implies x = -5\\\\\text{Substitute }~x=-5~ \text{in equation (ii):}\\\\2(-5) +5y =-35\\\\\implies -10 +5y = -35\\\\\implies 5y = -35 +10 = -25\\\\\implies y = - \dfrac{25}5 = -5[/tex]
[tex]\text{Hence,}~ \textbf{(x,y) = (-5, -5)}[/tex]