She determined that the solution is (-3, -3). Is she correct? If not, explain why.


ANo. She used the wrong slopes when graphing the equations.
BNo. She used the wrong y-intercepts when graphing the equations.
CNo. She switched the x and y values of the intersection point when writing the solution.
DYes, she is correct.

Verified Answer :

  • Verification requires substituting the point \((-3, -3)\) into both equations of the system.
  • Common errors in graphing include using incorrect slopes or y-intercepts, or incorrectly identifying the intersection point.
  • Since the specific equations were not provided, the correctness of the solution cannot be determined without testing the point against the system.
  • The final answer depends on the equations provided: \(\boxed{\text{Verification needed}}\).

Explanation

  1. Verification Procedure for a System of Equations

To determine if the point \((-3, -3)\) is the correct solution to a system of two linear equations, we must verify if this coordinate pair satisfies both equations simultaneously. A linear system of equations is given by:
\[ \begin{cases} y = m_1 x + b_1 \ y = m_2 x + b_2 \end{cases} \]
where \(m_1, m_2\) are the slopes and \(b_1, b_2\) are the y-intercepts. If the solution is \((-3, -3)\), then substituting \(x = -3\) and \(y = -3\) into both equations must yield true statements:
\[ -3 = m_1(-3) + b_1 \]
\[ -3 = m_2(-3) + b_2 \]
If these equations are satisfied, the point lies on both lines and is indeed the correct intersection point (the solution).

  1. Analysis of Potential Errors

When graphing or solving a system of equations, common errors can lead to incorrect conclusions. Let us analyze the provided options:

  1. Wrong slopes: If one calculates the slopes \(m_1\) or \(m_2\) incorrectly, the lines will be drawn at the wrong angle, leading to an incorrect intersection point.
  2. Wrong y-intercepts: If one calculates the y-intercepts \(b_1\) or \(b_2\) incorrectly, the lines will be shifted vertically, also leading to an incorrect intersection point.
  3. Switched x and y values: If the point of intersection is calculated as \((y, x)\) instead of \((x, y)\), the coordinates will be swapped. However, in the specific case of \((-3, -3)\), swapping the values does not change the result, as \(x = y = -3\).
  4. She is correct: This is true if the point \((-3, -3)\) satisfies both original equations.

Without the specific equations, we cannot verify if \((-3, -3)\) is correct. However, one can test the candidate point by substitution. If the substitution fails, one should re-evaluate the slopes and y-intercepts of the original equations.

  1. Conclusion regarding the Solution

To conclude, whether she is correct depends entirely on the specific equations provided in the original problem. If you are provided with a system of equations, substitute \(-3\) for \(x\) and \(-3\) for \(y\) in both. If both equations result in a true statement, she is correct. If not, verify the slope and intercept calculations, as these are the most common sources of error in graphical methods. Because the equations were not provided here, no definitive choice can be made among the options provided without the system itself.

Examples

In urban planning, architects often use systems of equations to find the intersection of two roads or utility lines. For instance, if one line is represented by \(y = 2x + 3\) and another by \(y = -x - 6\), we can find their intersection by setting them equal: \(2x + 3 = -x - 6\). Solving this gives \(3x = -9\), so \(x = -3\). Substituting back, \(y = 2(-3) + 3 = -3\). Thus, \((-3, -3)\) is the correct solution. Verifying such points is crucial to ensure that infrastructure plans are accurate and safe.