How did they rearranged the following formula

[Krack]

Hello.

Can someone please help me understand how the following formula was re-arranged to isolate fo qs.



Any specific material that you guys know that could help me understand this?

Thank you.

 

[lev888]

Factor out $σ_s$. You now have $σ_s * blah1 = blah2$. Can you isolate it now?

 

[BigBeachBanana]

They just factored out $\sigma_s$, and divide.
$$\sigma_s\left(\frac{A_s}{E_bA_b}+\frac{1}{E_s}\right)$$

 

[Krack]

Thanks fellas.