<p>If 0≤ x≤ y and (x+y)^2− (x−y)^2≥25, what
is the least possible value of y ?</p>
<p>answer= 5/2</p>
<p>x^2 + 2xy + y^2 - (x^2 - 2xy + y^2) >= 25 </p>
<p>4xy >= 25
xy >= 25/4 </p>
<p>sqrt(25/4) = 5/2 </p>
<p>This is the least possible value because y must be greater than or equal to x, so the least it can be is equal to x, which is 5/2.</p>