Hello!
The answers are:
First box: 7 times the cube of the sum of x and 8
Second box: 8 added to the cube of 7x.
Third box: 8 added to 7 and x cubed.
Fourth box: the cube of the sum of 7x and 8.
Why?
We are given the expression and we need to macth to the correct verbal description, so we have:
First box:

It's 7 times the cube of the sum of x and 8
Second box:

We have that "7x" is cubed and then, added to 8, so, it's 8 added to the cube of 7x.
Third box:

We have "7" times "x" cubed and added to 8, so it's 8 added to 7 and x cubed.
Fourth box:

We have "7x" added to 8, and the expression is cubed, so, it's the cube of the sum of 7x and 8.
Have a nice day!