Answer:
x = 7 and y = 0
Explanation:
We can either solve by substitution method or by elimination method or both method . We will solve by both the elimination and substitution method.
X+y=7 ---------------------------------------------------(1)
-x+y=-7 -------------------------------------------------(2)
Subtract equation (2) from equation(1)
2x = 14
Divide both-side of the equation by 2
2x/2 = 14/2
x = 7
Substitute x = 7 into equation (1)
x+y=7
7 + y = 7
Subtract 7 from both-side of the equation
7-7 + y = 7-7
y = 0
x = 7 and y =0