−2x−4y=−8 and 7x+5y=-177x+5y=−17 by combining the equations.
\big( -2x(−2x -4y−4y == -8\big)−8)
\big( 7x(7x +5y+5y == -17\big)−17)
-2x−2x -4y−4y == -8−8
7x7x +5y+5y == -17−17
0
0xx ++
0
0yy ==