That’s 29 I thinking I don’t know
We are given this

write it as the difference of cubes

use the formula for the difference of cubes

Now use the formula for the difference of squares as 

On the X side it’s +1
Hopefully this helps
Answer:
75+12h ≥ 399
He must work at least 27 hours
Step-by-step explanation:
How much does benny earn
He makes 75 for the course plus 12 dollars an hour
75+ 12h
This must be at least 399
75+12h ≥ 399
Subtract 75 from each side
75-75+12h ≥ 399-75
12h ≥ 324
Divide each side by 12
12h/12 ≥ 324/12
h ≥ 27
He must work at least 27 hour