document.write( "Question 1209886: Find the area of the region determined by the system
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document.write( "y \ge |x|, \\
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document.write( "y \le -|2x + 1| + 6. \n" );
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Algebra.Com's Answer #850958 by CPhill(1959)![]() ![]() You can put this solution on YOUR website! Let's analyze the inequalities to determine the region.\r \n" ); document.write( "\n" ); document.write( "1. **$y \ge |x|$**\r \n" ); document.write( "\n" ); document.write( " * This represents the region above the V-shaped graph of $y = |x|$. \n" ); document.write( " * $y = x$ for $x \ge 0$ \n" ); document.write( " * $y = -x$ for $x < 0$\r \n" ); document.write( "\n" ); document.write( "2. **$y \le -|2x + 1| + 6$**\r \n" ); document.write( "\n" ); document.write( " * This represents the region below the inverted V-shaped graph of $y = -|2x + 1| + 6$. \n" ); document.write( " * To find the vertex of $y = -|2x + 1| + 6$, we set $2x + 1 = 0$, which gives $x = -\frac{1}{2}$. \n" ); document.write( " * When $x = -\frac{1}{2}$, $y = -|0| + 6 = 6$. So, the vertex is $(-\frac{1}{2}, 6)$. \n" ); document.write( " * For $2x + 1 \ge 0$, i.e., $x \ge -\frac{1}{2}$, $y = -(2x + 1) + 6 = -2x + 5$. \n" ); document.write( " * For $2x + 1 < 0$, i.e., $x < -\frac{1}{2}$, $y = -(-2x - 1) + 6 = 2x + 7$.\r \n" ); document.write( "\n" ); document.write( "Now, we need to find the intersection points of the graphs.\r \n" ); document.write( "\n" ); document.write( "**Intersection of $y = |x|$ and $y = -|2x + 1| + 6$:**\r \n" ); document.write( "\n" ); document.write( "* **Case 1: $x \ge 0$ and $x \ge -\frac{1}{2}$ (i.e., $x \ge 0$)** \n" ); document.write( " * $x = -2x + 5$ \n" ); document.write( " * $3x = 5$ \n" ); document.write( " * $x = \frac{5}{3}$ \n" ); document.write( " * $y = \frac{5}{3}$ \n" ); document.write( " * Intersection point: $(\frac{5}{3}, \frac{5}{3})$\r \n" ); document.write( "\n" ); document.write( "* **Case 2: $x < 0$ and $x \ge -\frac{1}{2}$ (i.e., $-\frac{1}{2} \le x < 0$)** \n" ); document.write( " * $-x = -2x + 5$ \n" ); document.write( " * $x = 5$ (This is not in the interval, so no intersection)\r \n" ); document.write( "\n" ); document.write( "* **Case 3: $x \ge 0$ and $x < -\frac{1}{2}$ (Impossible)**\r \n" ); document.write( "\n" ); document.write( "* **Case 4: $x < 0$ and $x < -\frac{1}{2}$ (i.e., $x < -\frac{1}{2}$) ** \n" ); document.write( " * $-x = 2x + 7$ \n" ); document.write( " * $-3x = 7$ \n" ); document.write( " * $x = -\frac{7}{3}$ \n" ); document.write( " * $y = \frac{7}{3}$ \n" ); document.write( " * Intersection point: $(-\frac{7}{3}, \frac{7}{3})$\r \n" ); document.write( "\n" ); document.write( "The intersection points are $(\frac{5}{3}, \frac{5}{3})$ and $(-\frac{7}{3}, \frac{7}{3})$.\r \n" ); document.write( "\n" ); document.write( "Now, we need to find the area of the region.\r \n" ); document.write( "\n" ); document.write( "We can split the area into two triangles.\r \n" ); document.write( "\n" ); document.write( "* Triangle 1: Vertices $(-\frac{7}{3}, \frac{7}{3})$, $(-\frac{1}{2}, 6)$, and $(0, 0)$. \n" ); document.write( "* Triangle 2: Vertices $(0, 0)$, $(-\frac{1}{2}, 6)$, and $(\frac{5}{3}, \frac{5}{3})$.\r \n" ); document.write( "\n" ); document.write( "Area of Triangle 1: \n" ); document.write( "Using the determinant formula: \n" ); document.write( "$$ \frac{1}{2} \left| (-\frac{7}{3})(6 - 0) + (-\frac{1}{2})(0 - \frac{7}{3}) + 0(\frac{7}{3} - 6) \right| $$ \n" ); document.write( "$$ \frac{1}{2} \left| -14 + \frac{7}{6} \right| = \frac{1}{2} \left| \frac{-84 + 7}{6} \right| = \frac{1}{2} \left| \frac{-77}{6} \right| = \frac{77}{12} $$\r \n" ); document.write( "\n" ); document.write( "Area of Triangle 2: \n" ); document.write( "$$ \frac{1}{2} \left| 0(6 - \frac{5}{3}) + (-\frac{1}{2})(\frac{5}{3} - 0) + (\frac{5}{3})(0 - 6) \right| $$ \n" ); document.write( "$$ \frac{1}{2} \left| -\frac{5}{6} - 10 \right| = \frac{1}{2} \left| \frac{-5 - 60}{6} \right| = \frac{1}{2} \left| \frac{-65}{6} \right| = \frac{65}{12} $$\r \n" ); document.write( "\n" ); document.write( "Total area: \n" ); document.write( "$$ \frac{77}{12} + \frac{65}{12} = \frac{142}{12} = \frac{71}{6} $$\r \n" ); document.write( "\n" ); document.write( "Final Answer: The final answer is $\boxed{\frac{71}{6}}$ \n" ); document.write( " \n" ); document.write( " |