Respuesta :
Answer:
Step-by-step explanation:
From the problem statement, we can set up the following two equations:
[tex]L = 2W + 2[/tex]
[tex]40 = L * W[/tex]
Plugging the first equation into the second, we can solve for [tex]W[/tex]:
[tex]40 = L * W[/tex]
[tex]40 = (2W + 2) * W[/tex]
[tex]40 = 2W^{2} + 2W[/tex]
[tex]2W^{2} + 2W - 40 = 0[/tex]
[tex]W^{2} + W - 20 = 0[/tex]
[tex](W + 5)(W - 4) = 0[/tex]
[tex]W = -5, 4[/tex]
Since the length must be a positive number, then we know that [tex]W = 4[/tex]. We can now plug this number into the second equation to get [tex]L[/tex]:
[tex]40 = L * W[/tex]
[tex]40 = L * (4)[/tex]
[tex]L = 10[/tex]
Answer:
Step 1
Let length and breadth be x and y respectively
Given
x=2+2y
Step 2
Area of rectangle is lengthxbreadth
Therefore
area=x times y
Area=(2+2y)*y
=2y+2y^2
Area=40
Step 3
40=2y+2y^2
2y^2+2y-40=0
The roots are - 8 and 10
The equation is:
2y^2+10y-8y-40=0
2y(y+5)-8(y+5)=0
Which gives
y=-5 and y=4
Y=5 Rejected,
Therefore
y=4,breadth=4
So length=10(2*4+2)