Can you help to find a number in Circle of Triangle on Q3 of the picture
For 3 (a) ... (see diagram). I labeled the corner values $a$, $b$, and $c$. Set up three equations.
$a+b=-1$
$b+c=-6$
$a+c=-9$
Solve the system of equations ... you should get $a=-2 $, $b=1$, and $c=-7$