Let us assume the cost of the camera at the photography store = $x.
We are given $126 is 2/3 of the price that a photography store charges.
Let us repharse above statement "$126 is 2/3 of the store price x".
Let us convert above statement in an equation now.
126 = 2/3 of x.
126 = 2/3 x.
Dividing both sides by 2/3, we get
126 ÷ 2/3 =2/3 x ÷ 2/3.
126 × 3/2 = x
378/2 =x.
x= 189.
Therefore, the cost of the camera at the photography store is $189.