a+b+c=123
b=2a-9
c=3a+6
Substitute the values of b and c into the first equation
a+(2a-9)+(3a+6)=123
Combine like terms
6a-3=123
6a=126
a=21
Plug this a value into the second and third equation to get the b and c values.
b=2(21)-9
b=42-9
b=33
c=3(21)+6
c=63+6
c=69
Final answer:
a=21
b=33
c=69
