We can use the following formula to solve this problem:
[tex]p=\frac{n-o}{o}[/tex]Where p is the percent given as a decimal, n is the new earning and o is the original one. Replace for the given values and then solve for o:
[tex]\begin{gathered} 0.12=\frac{134400-o}{o} \\ 0.12o=134400-o \\ o+0.12o=134400 \\ 1.12o=134400 \\ o=\frac{134400}{1.12} \\ o=120000 \end{gathered}[/tex]It means that she made $120000 last year
