Answer:
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Step-by-step explanation:
something about a formula lol i learned this yesterday i just dont know how to explain
According to my test it is 9 so it should be right
You only have to sum the expressions of the two functions:

Answer:
The perimeter of rectangle is 48 cm.
Step-by-step explanation:
First, you have to form an expression for the length and the width. Let x be the width :
width = x cm
length = 3 × x = 3x cm
Then, you have to apply area of rectangle formula, A = length × width to find the value of x.Let area equals to 108 :
A = length × width
108 = 3x × x
3x² = 108
x² = 108 ÷ 3
x² = 36
x = √36
x = 6 cm
Lastly, you have to find perimeter :
length = 3 × 6 = 18 cm
width = 6 cm
Perimeter = 2(length + width)
P = 2(18 + 6)
P = 2(24)
P = 48 cm