Step-by-step explanation:
Given :-
Adding the equations :-
[tex]: \implies[/tex] 10y = -10
[tex]: \implies[/tex] y = -1
Put it (i) :-
[tex]: \implies[/tex] 4x - 8 = 20
[tex]: \implies[/tex] 4x = 20 + 8
[tex]: \implies[/tex] 4x = 28
[tex]: \implies[/tex] x = 28/4
[tex]: \implies[/tex] x = 7