Answer:
-5; 4
Step-by-step explanation:
The given linear system is:
[tex]x_1+4x_2=11\\2x_1+7x_2=18[/tex]
Multiplying the first equation by -2 and adding to the second gives:
[tex]x_1+4x_2=11\\2x_1-2x_1_+7x_2-8x_2=18 -22\\\\x_1+4x_2=11\\-x_2=-4[/tex]
Multiply the second equation by 4 and add to the first to find x1:
[tex]x_1+4x_2-4x_2=11-16\\-x_2=-4\\\\x_1=-5\\x_2=4[/tex]
The order pair for the solution of the system is -5; 4.
