Math Problem Statement

The diagram shows the graph of y = 4x^2 + x - 14. It cuts the x-axis at two points A and B, and the y-axis at the point C. Find: (i) the coordinates of A and C, (ii) the equation of the line of symmetry.

Solution

The image shows a quadratic equation y=4x2+x14y = 4x^2 + x - 14 and a diagram of its graph. The graph cuts the x-axis at points A and B, and intersects the y-axis at point C. The problem asks for:

  1. The coordinates of points A and C.
  2. The equation of the line of symmetry.

Part (i) - Coordinates of Points A and C

  • To find point A and B (x-intercepts): Set y=0y = 0 and solve the quadratic equation: 4x2+x14=04x^2 + x - 14 = 0 We can solve this using the quadratic formula: x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} where a=4a = 4, b=1b = 1, and c=14c = -14.

  • To find point C (y-intercept): Set x=0x = 0 and solve for yy.

Part (ii) - Equation of the Line of Symmetry

The line of symmetry for a quadratic function y=ax2+bx+cy = ax^2 + bx + c is given by: x=b2ax = \frac{-b}{2a}

I will calculate both the coordinates of points A and C, as well as the equation of the line of symmetry. Let's begin the calculations.### Solutions:

  1. Coordinates of Points A and B (x-intercepts):

    • A(1.75,0)A(1.75, 0)
    • B(2,0)B(-2, 0)
  2. Coordinates of Point C (y-intercept):

    • C(0,14)C(0, -14)
  3. Equation of the Line of Symmetry:

    • x=0.125x = -0.125

Would you like further details on any step, or do you have any other questions?

Here are 5 related questions to explore further:

  1. How do you derive the quadratic formula?
  2. What is the significance of the discriminant in quadratic equations?
  3. How do you graph a quadratic equation by hand?
  4. Can the vertex of a parabola be used to find the maximum or minimum value?
  5. How does completing the square help in solving quadratic equations?

Tip: When solving quadratic equations, always check the discriminant to know the nature of the roots.

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Math Problem Analysis

Mathematical Concepts

Quadratic Equations
Parabolas
Symmetry

Formulas

Quadratic equation formula: ax^2 + bx + c = 0
Quadratic formula: x = (-b ± sqrt(b^2 - 4ac)) / 2a
Line of symmetry formula: x = -b / 2a

Theorems

Quadratic Formula Theorem
Symmetry of Parabolas

Suitable Grade Level

Grades 9-11