Use the substitution method to solve the system of equations. choose the correct ordered pair.

x + y = 3
y = 9

  [B]:  " (-6, 9) " .

Explanation:

Given the following system of equations:

x + y = 3 ;

y = 9 ;


Substitute "9" for "y" in the first equation; to solve for "x";  we already have our value for "y" ;   "y = 9 " ; (given) ;


      x + 9 = 3 ;

Subtract "9" from EACH side of the equation;

     x + 9 − 9 = 3 − 9 ;

to get:

         x = -6 .


Check our 

x + y = 3

-6 + 9 =? 3 ?   Yes!

The answer for the system of equations is: 

     x = -6,  y = 9 ;  or, write as:  (-6, 9) .

   which is:  Answer choice:  [B]:  " (-6, 9) " .