1.
distance between (1, 1) and (4, 7) = \(\sqrt{(4-1)^2+(7-1)^2}\ =\ \sqrt{9+36}\ =\ \sqrt{45}\ =\ 3\sqrt5\)
2.
Let x be the thickness of the walls in feet. | |
(12 - 2x)(17 - 2x) = 176 |
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204 - 24x - 34x + 4x2 = 176 | |
4x2 - 58x + 204 = 176 |
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4x2 - 58x + 28 = 0 | |
4x2 - 2x - 56x + 28 = 0 |
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2x(2x - 1) - 28(2x - 1) = 0 | |
(2x - 1)(2x - 28) = 0 |
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x = 1/2 or x = 14 | |
x can't be 14 because that would make the walls thicker than the dimensions of the exterior of the room. |
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x = 1/2 is the solution. |