Answer: [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 answer:
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) " . _____________________________________
