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The area of the quadrilateral bounded by the YY-axis, the line x=5x=5, and the lines ∣x−y∣−∣x−5∣=2|x-y|-|x-5|=2, is

Entered answer:

Solution

✅ Correct Answer: 45

We need to find the area of a quadrilateral with these boundaries:

Left side: Y-axis (x=0x = 0)

Right side: Line x=5x = 5

Top and bottom: The equation ∣x−y∣−∣x−5∣=2|x-y| - |x-5| = 2 \newline\newline The key insight is that since our region is between x=0x = 0 and x=5x = 5, we know x≤5x \leq 5 always. This means ∣x−5∣=5−x|x-5| = 5-x. \newline\newline


\newline\newline Simplifying the equation:

∣x−y∣−∣x−5∣=2|x-y| - |x-5| = 2

∣x−y∣−(5−x)=2|x-y| - (5-x) = 2

∣x−y∣=2+5−x=7−x|x-y| = 2 + 5 - x = 7 - x \newline\newline


\newline\newline Removing the remaining absolute value gives us two cases: \newline\newline Case A: When x−y≥0x-y \geq 0 (meaning x≥yx \geq y):

x−y=7−xx - y = 7 - x

2x−y=72x - y = 7

y=2x−7y = 2x - 7 \newline\newline Case B: When x−y<0x-y < 0 (meaning x<yx < y):

−(x−y)=7−x-(x-y) = 7 - x

−x+y=7−x-x + y = 7 - x

y=7y = 7 \newline\newline


\newline\newline Finding the vertices where these lines meet x=0x = 0 and x=5x = 5: \newline\newline At x=0x = 0:

Line y=2x−7y = 2x - 7: y=2(0)−7=−7y = 2(0) - 7 = -7 → Point (0,−7)(0, -7)

Line y=7y = 7: y=7y = 7 → Point (0,7)(0, 7) \newline\newline At x=5x = 5:

Line y=2x−7y = 2x - 7: y=2(5)−7=3y = 2(5) - 7 = 3 → Point (5,3)(5, 3)

Line y=7y = 7: y=7y = 7 → Point (5,7)(5, 7) \newline\newline


\newline\newline Our quadrilateral has vertices: (0,−7)(0, -7), (0,7)(0, 7), (5,7)(5, 7), (5,3)(5, 3) \newline\newline This forms a trapezoid with:

Left side height: from y=−7y = -7 to y=7y = 7, so height =14= 14

Right side height: from y=3y = 3 to y=7y = 7, so height =4= 4

Width: 5−0=55 - 0 = 5 \newline\newline Using trapezoid formula: \newline\newline Area=12×(sum of parallel sides)×width\text{Area} = \dfrac{1}{2} \times (\text{sum of parallel sides}) \times \text{width} \newline\newline Area=12×(14+4)×5=12×18×5=45\text{Area} = \dfrac{1}{2} \times (14 + 4) \times 5 = \dfrac{1}{2} \times 18 \times 5 = 45

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