Quadratic functions and equations
• Quadratic functions: A function f given as
f(x) = a 𝑥2
+ b x + c, a ≠0, is called a quadratic function. The
graph of quadratic function is a parabola.
e.g. 1) f(x) = 𝑥2
− 4x + 5.
2) f(x) = 3 𝑥2
− 9 x + 13
are quadratic functions.
Quadratic equations
An equation of degree 2 is called quadratic equations.
General from: a x2 + b x + c = 0 where a, b, c, ∈ R and a ≠ 0.
The values of x satisfying the quadratic equation are called
roots of the equation.
Examples: 1) 3x2 + x + 5 = 0,
2) -x2 + 7x + 5 = 0,
3) x2 + x = 0
are the quadratic equations.
• There are three methods of solving the quadratic equations,
1) Factorizing of Quadratic Equation
2) Method of Completing the Square
3) Formula Method of Finding Roots
1) Factorizing of Quadratic Equation
Ex. Solve the following Quadratic Equations
1) x2 + 5x + 6 = 0
Sol.: x2 + 5x + 6 = 0
x2 + 2x + 3x + 6 = 0
x(x + 2) + 3(x + 2) = 0
(x + 2)(x + 3) = 0
Thus the two obtained factors of the quadratic equation are (x + 2) and
(x + 3)
i.e. x =-2 & x = -3.
2) x2 - 2x - 24 = 0
Sol.: x =-4 & x = 6.
2) Method of Completing the Square
Ex.1) Solve x2 + 4x + 4 =0
Sol: x2 + 4x + 4 =0
(x+2)2 = 0
(x+2)(x+2) =0
i.e. x= -2, -2
Ex.2) Solve x2 + 8x + 16 =0
THANK YOU

Quadratic functions and Equations.pdf

  • 1.
    Quadratic functions andequations • Quadratic functions: A function f given as f(x) = a 𝑥2 + b x + c, a ≠0, is called a quadratic function. The graph of quadratic function is a parabola. e.g. 1) f(x) = 𝑥2 − 4x + 5. 2) f(x) = 3 𝑥2 − 9 x + 13 are quadratic functions.
  • 2.
    Quadratic equations An equationof degree 2 is called quadratic equations. General from: a x2 + b x + c = 0 where a, b, c, ∈ R and a ≠ 0. The values of x satisfying the quadratic equation are called roots of the equation. Examples: 1) 3x2 + x + 5 = 0, 2) -x2 + 7x + 5 = 0, 3) x2 + x = 0 are the quadratic equations.
  • 3.
    • There arethree methods of solving the quadratic equations, 1) Factorizing of Quadratic Equation 2) Method of Completing the Square 3) Formula Method of Finding Roots 1) Factorizing of Quadratic Equation Ex. Solve the following Quadratic Equations 1) x2 + 5x + 6 = 0 Sol.: x2 + 5x + 6 = 0 x2 + 2x + 3x + 6 = 0 x(x + 2) + 3(x + 2) = 0 (x + 2)(x + 3) = 0 Thus the two obtained factors of the quadratic equation are (x + 2) and (x + 3) i.e. x =-2 & x = -3. 2) x2 - 2x - 24 = 0 Sol.: x =-4 & x = 6.
  • 4.
    2) Method ofCompleting the Square Ex.1) Solve x2 + 4x + 4 =0 Sol: x2 + 4x + 4 =0 (x+2)2 = 0 (x+2)(x+2) =0 i.e. x= -2, -2 Ex.2) Solve x2 + 8x + 16 =0
  • 5.