Find the value of the variable that makes each equation true.

1. $3x + 2 = 20$

   Step 1(a):

   If $3x + 2 = 20$, then $3x$ must be equal to $18$. Why?

   Step 2(a):

   If $3x = 18$, then each $x$ must be equal to $6$.
   Why does this make sense?
   Would any other number work?

   Answer (a):

   $6$

2. $2x - 1 = 23$

   Hint (b):

   You can use reasoning similar to that for part (a).