ok. so lets call the cost of each soda x. now, 3 packs of soda is 10 less than five packs of soda. so the price of 3 packs of soda is 3x, the price of five packs is 5x. now, it says that 3 packs is 10 less than five packs. that means that 3x=5x-10.
now, to find the price of a pack of soda, we have to isolate x.
add 10 to both sides to get 3x+10=5x. now, we subtact 3x on both sides to get 10=2x. divide by 2 on both sides, x=5. a pack of soda is 5 dollars
