Remember
and
if
where x=x then m=n
so
so
m+n=-6
so test the options
first one works
2nd ones doesn't
3rd one doesn't
4th one doesnt'
answer is first option, m=3 and n=-9
and
if
so
so
m+n=-6
so test the options
first one works
2nd ones doesn't
3rd one doesn't
4th one doesnt'
answer is first option, m=3 and n=-9