Form 4 Mathematics Chapter 2 c594j

Form 4 Mathematics

Chapter 2: Quadratic Expressions and Equations 2.1 Quadratic Expressions 1) Form: ax2 + bx + c, where a, b and c are constants, a≠0 and x is an unknown. Example: 4x2 + 2x - 1 and 4x2 – 9 2) The highest power of quadratic expressions is 2 which is the power of the unknown. 3) (x + a)(x + b) = x2 + ax + bx + ab Example: (x + 2)(x + 3) =

2.2 Factorisation of Quadratic Expressions x2 + ax + bx + ab = (x + a)(x + b) Example: x2 + 5x + 6

Example: 6x2+4x+3

When the second sign is positive, both signs in bracket are same. x2 + 5x + 6

When the second sign is negative, the signs in both bracket are different which one is positive, the other negative. 2x2 + 3x - 20

x2 - 4x + 4

4x2 - 2x - 1

Chapter 2: Quadratic Expressions and Equations

Form 4 Mathematics

a2x - b2 = (ax + b)(ax – b) Example: 4x2 - 9 =

2.3 Quadratic Equations Example: x2 + 5x = -6

Example: 2p2 + 3 = p – p2

2.4 Roots of Quadratic Equations x2 + 5x + 6 = 0

Chapter 2: Quadratic Expressions and Equations