Question

Instructions: Find the value of that completes the square and creates a perfect square trinomial.

Answer 1

Given the expression;

`x^2+18x+c`

c is the half of square of coefficient of x. That is;

`\begin{gathered} x^2+18x+c=x^2+18x+((1)/(2)(18))^2 \\ \\ x^2+18x+c=x^2+18x+9^2 \\ \\ x^2+18x+c=x^2+18x+81 \\ \\ x^2+18x+81=(x+9)(x+9) \end{gathered}`

Hence, the value of c is;

`c=81`