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4:01 .11 Previous 33 Next Unit Pretes Submit Test Reader Tools (i) Info Save \& Exit 33 Select the correct answer. How many solutions does this system of equations have? \[ \begin{array}{l} y=2 x+5 \\ y=x^{3}+4 x^{2}+x+2 \end{array} \] A. no solution B. 1 solution C. 2 solutions D. 3 solutions

Ask by Bowers Daniel. in the United States
Feb 03,2025

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Answer

The system has 3 solutions. **Answer: D. 3 solutions**

Solution

To determine how many solutions the system of equations has, we need to find the number of real solutions to the following system: \[ \begin{cases} y = 2x + 5 \\ y = x^3 + 4x^2 + x + 2 \end{cases} \] ### Step 1: Set the Equations Equal to Each Other Since both equations equal \( y \), we can set them equal to each other: \[ 2x + 5 = x^3 + 4x^2 + x + 2 \] ### Step 2: Rearrange the Equation Rearrange the equation to bring all terms to one side: \[ x^3 + 4x^2 - x - 3 = 0 \] ### Step 3: Analyze the Cubic Equation To determine the number of real roots of the cubic equation \( x^3 + 4x^2 - x - 3 = 0 \), we can use the following methods: **1. Rational Root Theorem:** - Possible rational roots are \( \pm1, \pm3 \). - Testing these, none satisfy the equation, indicating no rational roots. **2. Sign Changes:** Evaluate the function \( f(x) = x^3 + 4x^2 - x - 3 \) at various points: - \( f(-5) = -23 \) - \( f(-4) = 1 \) (Sign change from negative to positive → one root between -5 and -4) - \( f(-1) = 1 \) - \( f(0) = -3 \) (Sign change from positive to negative → one root between -1 and 0) - \( f(1) = 1 \) (Sign change from negative to positive → one root between 0 and 1) **3. Conclusion:** Since there are three sign changes, the cubic equation has **three real roots**. Therefore, the original system of equations has **three solutions**. ### Final Answer **D. 3 solutions**

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To determine how many solutions the given system of equations has, we must analyze the equations visually or algebraically. The first equation, \(y = 2x + 5\), represents a straight line with a slope of 2. The second equation, \(y = x^{3} + 4x^{2} + x + 2\), is a cubic polynomial, which can have up to 3 intersections (solutions) with the line. By graphing or calculating the points of intersection, you may find that the cubic function can cross the linear equation in various ways. Depending on the shape of the cubic graph, the equations could intersect at 0, 1, 2, or 3 points. In fact, since the cubic has a degree of 3, it can have up to 3 real solutions. However, considering the nature of polynomial growth (a cubic rises to infinity on both ends), it can intersect the line potentially at each turning point. Ultimately, determining the exact number of intersections may require further analysis of the derivative or specific values. In summary, without loss of generality, the answer is: D. 3 solutions.

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