Answer:
[tex]27[/tex]
Step-by-step explanation:
Let Sara's number be [tex]x[/tex]. Now, we can build an equation.
We have that [tex]-3(x-12)=-45[/tex]. Aha! Now we have a path to the solution!
We can divide both sides of the equation by [tex]-3[/tex] to get [tex]x-12=15[/tex].
Lastly, we add [tex]12[/tex] to both sides to get [tex]x=27[/tex].
So, Sara's number is [tex]\boxed{27}[/tex].
