Math Problem Statement

Trouver la forme factorisée de f(x) sachant que f est une fonction du second degré dont la courbe représentative intercepte l'axe des abscisses en 4 et en 5 et passe par le point de coordonnées (1,24).

Solution

The exercise requires finding the factorized form of second-degree functions based on given conditions.

1. Problem 1:

The curve of the quadratic function f(x)f(x) intercepts the x-axis at x=4x = 4 and x=5x = 5, and passes through the point (1,24)(1, 24).

  • The factorized form of a second-degree function that intercepts the x-axis at x=4x = 4 and x=5x = 5 is: f(x)=a(x4)(x5)f(x) = a(x - 4)(x - 5) Now, we need to find the constant aa using the fact that f(1)=24f(1) = 24. Substitute x=1x = 1 into the equation: 24=a(14)(15)24 = a(1 - 4)(1 - 5) 24=a(3)(4)24 = a(-3)(-4) 24=12a24 = 12a a=2a = 2 Thus, the factorized form is: f(x)=2(x4)(x5)f(x) = 2(x - 4)(x - 5)

2. Problem 2:

The curve of the quadratic function f(x)f(x) intercepts the x-axis at x=2x = -2, and passes through the point (1,1)(-1, -1).

  • The factorized form of a second-degree function that intercepts the x-axis at x=2x = -2 can be written as: f(x)=a(x+2)2f(x) = a(x + 2)^2 Since it passes through the point (1,1)(-1, -1), we substitute x=1x = -1 and f(x)=1f(x) = -1 into the equation to solve for aa: 1=a(1+2)2-1 = a(-1 + 2)^2 1=a(12)-1 = a(1^2) 1=a-1 = a Thus, the factorized form is: f(x)=(x+2)2f(x) = -(x + 2)^2

Would you like more details or have any questions?

Here are 5 related questions for further practice:

  1. What is the general factorized form of a quadratic function with given x-intercepts x1x_1 and x2x_2?
  2. How can you determine the value of aa in a quadratic function?
  3. How does the sign of aa affect the shape of a parabola?
  4. What happens if the quadratic function only touches the x-axis at one point?
  5. Can you convert the factorized form to standard form and vice versa?

Tip: Always use a known point (other than the x-intercepts) to solve for the coefficient aa in a quadratic function.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Factorization

Formulas

Quadratic equation formula ax^2 + bx + c = 0
Factorized form: f(x) = a(x - r1)(x - r2)

Theorems

Zero Product Property

Suitable Grade Level

Grades 9-11