1. ©G Dear2008 – Not to be sold/Free to use
Mathematic
(Preliminary)
Equations
Quadratic Formula
Stage 6 - Year 12
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©G Dear2008 – Not to be sold/Free to use

2. This method is often the last resort.
Equations
Solving by Formula
This method is often the last resort.
Formula
For ax2 + bx + c = 0
-b ±√b2 - 4ac 2a
x =

3. Equations Example -b ±√b2 - 4ac 2a x = For x2 + 4x + 2 = 0 a = 1,
-4 ±√8 2
x =
-4 ±2√2 2 =
-2 ±√2 =

4. Equations Example -b ±√b2 - 4ac 2a x = For 3x2 - 5x + 1 = 0 a = 3,
5 ±√13 6
x =