Question

By the end of the summer Margot has saved $375. Recall that each of the small pieces of wood costs $3.

Answer 1

375-3x=y
 
y=the amount of money left after buying x pieces of wood

Answer 2

So, we were given 2 variables, x and y. The amount of money that Margot has saved up, $375, and the cost of each piece of wood, $3.

So, if Margot buys x pieces of wood, it would cost her 3x (3 times x) dollars, and to find the remaining money, simply subtract what she had earlier to it. So the equation will be.

y = 375-3x

Hope this helps!