Sorry, it looks like you haven't got any of them right. That's ok, you'll be an expert in no time. Let's do one at a time.
Solve for Zt
Remember that to solve for a variable means to isolate it. So, we want to rearrange this formula so that Zt is by itself on either the right or the left side. Recall that we can manipulate the equation any way that we want, so long as we follow the Golden Rule of Algebra: Do unto one side as you do unto the other.
Step 1: Multiply both sides by Zt. This will cancel out the Zt on the right side and leave you with:
Step 2: Divide both sides by C. This cancels out the C from the left side, thereby isolating Zt:
Notice that in essence, all we have done is switched C and Zt. This will always work for equations of this form.
In general, if then
Do you understand this?