Select the correct answer. The equation can be solved by completing the square. What number should go in th for the first step? x^2-18x+ldots =4+ 324 81 18 9

To complete the square for the equation $x^2 - 18x + \ldots = 4$, we need to find the number that makes the left side a perfect square trinomial.<br /><br />The general form for a perfect square trinomial is $(x - a)^2 = x^2 - 2ax + a^2$. In this case, we need to find the value of $a$ that satisfies the equation.<br /><br />Comparing the given equation with the general form, we can see that $2a = 18$. Solving for $a$, we get $a = 9$.<br /><br />Therefore, the number that should go in the blank for the first step is 9.