Respuesta :

The number needed to complete the square is 9/4

Given the expression x^2 + 3x + ?

Using the completing the square;

Step 2: Get the coefficient of x

The coefficient of x is 3

Step 3: Get the half of coefficient of x

Hale of the coefficient  = 3/2

Step 4: Take the square of the result

Square of the result  = ()3/2)^2 = 9/4

Hence the number needed to complete the square is 9/4

Learn more on completing the square here: https://brainly.com/question/1596209