Stephanie M. answered 05/06/15
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Private Tutor - English, Mathematics, and Study Skills
(a) Let's find the side lengths of each box. Since these boxes are square, and Area = side2, we can take the square root of the area to find the length of a side. Factor each equation:
4x2 + 40x + 100
(2x + 10)(2x + 10)
(2x + 10)2
First box's side length: 2x + 10 meters
x2
Second box's side length: x meters
x2 + 40x + 400
(x + 20)(x + 20)
(x + 20)2
Third box's side length: x + 20
So, how many meters longer is the third box than the second box? Subtract:
(x + 20) - x
x + 20 - x
20 meters
(b) Let's set the area of box 1 equal to the areas of box 2 and 3 and solve for x:
4x2 + 40x + 100 = x2 + x2 + 40x + 400
4x2 + 40x + 100 = 2x2 + 40x + 400
2x2 + 40x + 100 = 40x + 400
2x2 + 100 = 400
2x2 = 300
x2 = 150
x = √150 ≈ 3.87 meters
(c) By "Grid 3," I'll assume you just mean box 3.
The length of box 1 is 10 meters longer than the length of box 3. So:
2x + 10 - 10 = x + 20
2x = x + 20
x = 20
Plug x = 20 into each area equation and sum them together:
4(20)2 + 40(20) + 100 + (20)2 + (20)2 + 40(20) + 400
4(400) + 800 + 100 + 400 + 800 + 400
1600 + 900 + 1200 + 400
2500 + 1600
4100 square meters