Answer:
54 - 3d
Explanation:
In order to find the cost of 3 DVDs we would simply need to multiply the expression given by 3. In order to do so we must use the distributive property and distribute the 3 to both the initial price of the dvd and the discount price, like so...
3(18 - d) ... in order to distribute we multiply 3 by 18 and then by d seperately
(3 * 18) - (3 * d)
54 - 3d
That would leave us the expression 54 - 3d