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Learn about adding, subtracting, multiplying, and dividing surds, as well as solving quadratic equations using different methods, including factorising and the quadratic formula. Understand real and complex solutions. Worksheets provided.
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Surds and Quadratics AS 91577
Surds • Adding • Subtracting • Multiplying • Dividing
Dividing surds(Rationalising)Example 1 Multiply top and bottom by
Dividing surds(Rationalising)Example 2 Multiply top and bottom by
Quadratics General formula:
Example 1. Solving for the roots (i.e. y = 0) Method 1: Factorising
Method 3: Graphics Calculator • Equation Mode • F2: Polynomial • Degree: 2 (F1) • Enter 1, -2, -3 • Solve (F1)
Example 2 Method 1: Factorize
Example 3 Equation cannot be factorised.
Using quadratic formula We use the substitution A complex number
Equation has 2 complex solutions Real part Imaginary Part
Note: Because the coefficients are real, solutions come in conjugate pairs i.e.
Forming quadratic equations from 2 solutions. If solutions are
Example 1 Quadratic equation is
Example 2 Quadratic equation is