Step-by-step explanation:
I understand the equation is
4mA = d - f³
to solve for A means to bring A alone on one side of the equation, and everything else to the other side of the equation.
1. remove the factor 4 from A by dividing both sides by 4.
mA = (d - f³)/4
2. remove the factor m from A by dividing both sides by m.
A = (d - f³)/4/m = (d - f³)/(4m)
that's it.