Question 1162832
<br>
None of the answer choices is correct.<br>
Answer choices b, c, and d make no sense at all...!<br>
I suspect answer choice a was supposed to be the right answer; but you don't show it right in your post.<br>
I will assume that answer choice a is supposed to be<br>
{{{(10y^2+x-1)(-10y^2+x-1)}}}<br>
Then you can see that it is right be rewriting it:<br>
{{{(10y^2+x-1)(-10y^2+x-1)}}}
{{{(x-1+10y^2)(x-1-10y^2)}}}
{{{((x-1)+10y^2)((x-1)-10y^2)}}}
{{{(x-1)^2-(10y^2)^2}}}  [using the pattern {{{(a+b)(a-b) = a^2-b^2}}}]
{{{x^2-2x+1-100y^4}}}<br>