Question

solve graphically
x+y=12
2x-y=3​

Answer 1

x=12-y. (3).

put in eqn 2

2x -y =3

2(12-y)-y=3

24-2y-y=3

24-3y=3

-3y=3-24

-3y=-21

y=7

put in eqn 3

x=12-7

x=5