Question

daca x+2y=17 si y-3y=4

Answer 1

$y - 3y = 4$

$- 2y = 4 \: | \div ( - 2)$

$y = - 2$

$x + 2y = 17$

$x + 2 \times ( - 2) = 17$

$x - 4 = 17$

$x = 17 + 4$

$x = 21$