Question

-2x-y=-9 5x-2y=18 substitution

Answer 1

$-2x-y=-9 \\ 5x-2y=18 \\ \\ \hbox{solve the first equation for y:} \\ -2x-y=-9 \ \ \ |+2x \\ -y=-9+2x \ \ \ |\times (-1) \\ y=9-2x \\ \\ \hbox{substitute 9-2x for y in the second equation:} \\ 5x-2(9-2x)=18 \\ 5x-18+4x=18 \\ 9x-18=18 \ \ \ |\div 9 \\ x-2=2 \ \ \ |+2 \\ x=4 \\ \\ y=9-2x=9-2 \times 4=9-8=1 \\ \\ \boxed{(x,y)=(4,1)}$

Answer 2

-2x-y = -9 5x-2y=18 -solve for y in terms of x -y= 2x-9 y=-2x+9 substitute 5x-2 ( -2x+9)=18 5x+4x -18=18 9x-18=18 9x= 36 x=4 substitute for x -2 (4) -y= -9 -8 -y = -9 -y = -1 y= 1 ANSWER x= 4 y=1 hope this helps