The numbers which should be placed in the boxes from left to right, when Juanita factor the expression, is 6 and 3 respectively.
<h3>What is a factor of polynomial?</h3>
The factor of a polynomial is the terms in linear form, which are, when multiplied together, give the original polynomial equation as a result.
Juanita begins to factor an expression as shown.

To find the value of blank, we have to factor the left-hand side expression using the split the middle term method as,

Hence, the numbers which should be placed in the boxes from left to right, when Juanita factor the expression is 6 and 3 respectively.
Learn more about factor of polynomial here;
brainly.com/question/24380382