Answer:
51-10sqrt(2)
Step-by-step explanation:
(a-b)^2=a^2-2ab+b^2
(5sqrt(2)-1)^2=(5sqrt(2))^2-2(5sqrt(2))(1)+1^2
=5^2(2)-2(5sqrt(2))(1)+1^2
=25(2)-10sqrt(2)+1
=50-10sqrt(2)+1
=51-10sqrt(2)
