Final answer:
To make x² + x a perfect-square trinomial, we need to add the value 0.25.
Step-by-step explanation:
To make the expression x² + x a perfect-square trinomial, we need to add a certain value. A perfect-square trinomial is in the form (x + a)², where a is a constant. In this case, we want x² + x to be in the form (x + a)², so we need to find the value of a. To do this, we can take half of the coefficient of the x term and square it. The coefficient of the x term is 1, so half of 1 is 0.5 and squaring it gives us 0.25. Therefore, the value that needs to be added to x² + x to make it a perfect-square trinomial is 0.25.
Learn more about Perfect-square trinomials