Answer:
a= -12 and b=36
Explanation:
a+b=24 and 3a+b
a-3a+b=24
-2a+b-b=24
-2a/-2=24/-2
a= -12
then substitute the value of a in a+b=24 to get the value of b
so let see -12+b=24
b=24+12
b=36
we can check it by the equation -2a+b-b=24
-2(-12)+36-36=24
24=24 so as you have seen the answer is correct
thanks!!!