Vanessa tried to solve an equation step by step.
\qquad\begin{aligned} -12&=4(f-6) \\ -12&=4f-24&\green{\text{Ste p } 1} \\ 12&=4f&\blue{\text{Step } 2} \\ 4&=f&\purple{\text{Step } 3} \end{aligned}
−12
−12
12
4


=4(f−6)
=4f−24
=4f
=f


Step 1
Step 2
Step 3


Find Vanessa's mistake.