16. Stuck on 16 can anyone help?

What is the missing constant term in the perfect square that starts with x^2 -20x

Hello people, i have a math question that i need with, me, i will give the correct one brainiest, and for the other correct people, a and 5 stars.

How many of the 250 grandparents in the population would you expect to prefer online shopping with merchant a? merchant a: 4 merchant b: 6 merchant c: 2 merchant d: 3 other: 5 none: 5 answer choices: a. about 4 b. about 8 c. about 40 d. about 21