Question

{-5x+3y= -4
{7x-5y= 4

Answer 1

$- 5x + 3y = - 4 ( \times 5)\\ + 7x - 5y = 4( \times 3) \\ \\ - 25x + 15y = - 20 \\ + 21x - 15y = 12 \\ \\ - 25x + 21x + 15y - 15y = - 20 + 12 \\ - 4x = - 8( \times - 1) \\ 4x = 8 \\ x = \frac{8}{4} \\ x = 2$



$- 5x + 3y = - 4 \\ - 5(2) + 3y = - 4 \\ - 10 + 3y = - 4 \\ 3y = - 4 + 10 \\ 3y = 6 \\ y = \frac{6}{3} \\ y = 2$

S={2;2}