Math Problem Statement

Solve the system of equations by graphing: y = -x^2 + 2x + 4 and y = 2x + 4.

Solution

To solve the given system of equations by graphing:

  1. Equations:

    • y=x2+2x+4y = -x^2 + 2x + 4 (a parabola)
    • y=2x+4y = 2x + 4 (a straight line)
  2. Steps to solve:

    • Graph y=x2+2x+4y = -x^2 + 2x + 4:

      • This is a downward-opening parabola because the coefficient of x2x^2 is negative.
      • Vertex: The vertex is at x=b2a=22(1)=1x = -\frac{b}{2a} = -\frac{2}{2(-1)} = 1. Substituting x=1x = 1 into the equation gives y=12+2(1)+4=5y = -1^2 + 2(1) + 4 = 5. So, the vertex is (1,5)(1, 5).
      • Additional points can be found by substituting other xx-values.
    • Graph y=2x+4y = 2x + 4:

      • This is a straight line with slope 22 and yy-intercept 44.
      • The points (0,4)(0, 4) and (1,6)(1, 6) can be plotted.
  3. Find intersections:

    • Set the two equations equal to each other: x2+2x+4=2x+4-x^2 + 2x + 4 = 2x + 4 Simplify: x2=0-x^2 = 0 x=0x = 0 Substitute x=0x = 0 back into one of the equations, e.g., y=2x+4y = 2x + 4: y=4y = 4 The intersection is at (0,4)(0, 4).

The system has one solution, (0,4)(0, 4).

Would you like me to verify or expand any steps?


Related Questions:

  1. What are the key features of parabolas, and how do they affect graphing?
  2. How do we determine the vertex and axis of symmetry of a quadratic equation?
  3. What are alternative methods for solving systems of equations apart from graphing?
  4. How can the slope-intercept form of a line be derived and used effectively?
  5. What conditions determine the number of solutions for a system of linear and quadratic equations?

Tip: For cleaner graphing, always use precise values for the vertex and intercepts to plot curves or lines.

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Math Problem Analysis

Mathematical Concepts

Graphing
Quadratic Equations
Linear Equations
Systems of Equations

Formulas

y = ax^2 + bx + c for parabolas
y = mx + b for lines

Theorems

Intersection of functions

Suitable Grade Level

Grades 8-10