Question

Which ordered pair is the solution to the system of equations?

{x+y=4
{x−y=−6


(−2, 4)(−2, 4)

(2, 2)(2, 2)

(1, −7)(1, −7)

(−1, 5)

Answer 1

hello :
{x+y=4....(1)
{x−y=−6....(2)
(1)+(2) : x+x+y-y = 4+(-6)
2x = -2 
x= -2/2 = -1
subsct in (1) : -1  +y = 4
y = 5 
the solution is : (−1, 5)