Answer
first number is 14, second number is -3
Work Step by Step
first number + 2*second number = 8
2*first number +second number = 25
$x+2y=8$
$2x+y=25$
$x+2y=8$
$-2*(x+2y=8)$
$-2x-4y=-16$
$2x+y=25$
$-2x-4y=-16$
$-2x-4y+(2x+y)=-16+25$
$2x-2x+y-4y=25-16$
$-3y=9$
$-3y/-3=9/-3$
$y=-3$
$2x+y=25$
$2x-3=25$
$2x=28$
$2x/2=28/2$
$x=14$