Which expression is a sum of cubes?

We have been given 4 expressions. We are asked to choose the expression that represents sum of cubes.

We know that sum of cubes is in form .

We can see that 1st and 2nd option has a negative sign. Therefore, these options cannot be sum of cubes.

Let us check 3rd and 4th options one by one.

We can rewrite our expression by writing terms as cubes:

Therefore, expression is a sum of cubes.

In 4th expression, we can see that . We cannot represent it as a cube. Similarly, we cannot represent as a cube. Therefore, 4th expression is not correct.

the number of the people going.

step-by-step explanation:

the cost to buy one movie ticket is $7. if the total cost for the movie is a function of how many people go, then the input is : the number of the people going.

3 is greater then both of those numbers