Question 1189079
<pre>

This is basic algebra, so I stongly encourage you to practice this until you know it cold.  Otherwise it will hinder you during your learning of more advanced topics.

1.  Solve P = 2l + 2w,  for l

Step-by-step...
    Subtract 2w from both sides (performing valid operation on both sides does not change the equality):
     P - 2w = 2l + 2w - 2w
    
    Simplify:
     P - 2w = 2l

    Divide both sides by 2:
     (P - 2w)/2 = 2l/2

    Simplify:
     (P - 2w)/2 = l  

    Re-write with l on left hand side:
      {{{ highlight( l = (P-2w)/2) }}}

When you have mastered this, you will do most of the above steps in your head.

2.   C = (5/9)(F - 32)

    i) Multiply both sides by (9/5)  & simplify
      (9/5)C =  (5/9)(F - 32)*(9/5)   
       // On right hand side, notice (5/9)*(9/5) = 1
      (9/5)C =  F - 32

    ii) Add 32 to both sides  & simplify
       (9/5)C + 32 = F - 32 + 32
       (9/5)C + 32 = F

        {{{ highlight( F = (9/5)C + 32) }}}

-----

When you hear "move the 2 to the other side"  it really means "do the opposite operation to both sides of the equation"
 
For example:  Solve for x:  y = 2x + 12

"move the 12 to the other side" means to subtract 12 from both sides (the subtraction "undoes" the addition on the right):  y - 12 = 2x + 12 -12

y - 12 = 2x   (one normally doesn't first write  2x + 12 - 12)

"move the 2 to the left hand side"  here means divide both sides by 2:
 (y - 12)/2 = x  

Now we re-write with x on the left hand side:
  x = (y - 12)/2