Solve the system by graphing

8x-6=-18
6y-8x=18
divide 1 equation by 2
4x-3y=-9
divide 2 equation by -2
-4x-3y=-9
this makes both equation dependent
slope intercept of two equation
4x-3y=-9
3y=4x+9
this makes this consistent.
Just helping if I can.

In 1992 the life expectancy of males in certain a countrywas 66.5 years in 1996 it was 69.4 years let E represent the life expectancy in year t and let t represent the number of years E(t)= ?T+ ? round to the nearest tenth

E12=?