<PRE><B>Question 1180749</B>
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The first tutor carelessly provided an incomplete solution to the problem.&lt;br&gt;
The second tutor pompously provided a lengthy response full of wonderful math which unfortunately has nothing to do with the problem....&lt;br&gt;
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We need to find the value(s) of k that make x^2-kx+81 a perfect square:&lt;br&gt;
{{{(x-a)^2 = x^2-2ax+a^2 = x^2-kx+81}}}&lt;br&gt;
Equating the constant terms, we see a^2=81, which means a can be either 9 or -9.&lt;br&gt;
Then equating the linear terms, we see that k=2a, which makes k either 18 or -18.&lt;br&gt;
ANSWERS: k = 18 or k = -18&lt;br&gt;
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