Explanation:
By definition, the area of a rectangle is given by:
A = w * lA=w∗l
Where,
w: width of the rectangle
l: length of the rectangle
We then have the following expression for the area:
A = k ^ 2 + 19k + 60A=k
2
+19k+60
What we must do is factorize the expression following the following steps:
1) Find two numbers that are equal to 19
2) Find two multiplied numbers equal to 60
We have then:
A = (k + 15) (k + 4)A=(k+15)(k+4)
Therefore, the width of the rectangle is:
w = (k + 4)w=(k+4)