Question 977321

x^2+kx+36 what is the value of k for which the expression is a perfect square trinomial
<pre>
Complete the square to get a perfect square trinomial
{{{x^2 + kx + 36}}}
This means that: {{{((1/2)k)^2 = 36}}}
{{{(k/2)^2 = 36}}}
{{{k/2 = " " +-sqrt(36)}}} ------ Taking square root of both sides
{{{k/2 = " " +- 6}}}
{{{k = " " +- 2(6)}}} ------- Cross-multiplying
{{{highlight_green(k = " " +- 12)}}}