Answer
$x^2-10x+25$
Work Step by Step
A binomial squared is equal to the square of the first term plus or minus twice the product of both terms plus the square of the second term.
$(a - b)^2= a^2 - 2ab + b^2$
$(x-5)^2=x^2-2(x)(5)+5^2=x^2-10x+25$