Answer:
Correct answer is D. x^2 + 81 = x^2 + 20x + 100
Step-by-step explanation:
root x^2 + 81 = x + 10
x^2 + 81 = (x + 10) ^2
we all know (a +b)^2 is a^2 + b^2 + 2ab
x^2 + 81 = x^2 + 10^2 + 2(10x)
x^2 + 81 = x^2 + 100 + 20x
