Answer:
The term was obtained by grouping and adding the all x terms in the expression.
Step-by-step explanation:
The example has already provided this step:
(x -4) +(x +1) +(¼x +5)=
Thus, the question is asking how is derived from the expression.
The attached picture shows the intermediate working to arrive at the final perimeter expression.
This expression is later equated to 20 since it is given that the perimeter of the traingle is 20 inches.
