Answer:
[tex]3a+a-15=225[/tex]
Step-by-step explanation:
We have the two equations as,
3a+b=225 and b=a-15
So in the substitution involved here its better if we substitute the second equation into first one.
We have the term b=a-15 so on directly substituting we get
4a=240,
a=60.
hence b would be 45.
In this way its better to substitute second one in the first one giving the following,
[tex]3a+a-15=225[/tex]
