See https://web2.0calc.com/questions/help_69037.
Answer:
81-25k²
Step-by-step explanation:
We need to write the expression for "The quantity 81 minus 5k, squared".
Square of any number x is given by x².
Square of 5k is given by : (5k)²= 5²×k²=25k²
Now subtract 25k² from 81.
It means we get : 81-25k². It is required expression.