Surds

Surds

1. √a x √b = √ab

2. √a/√b = √a/b

3. √a + √b = √a + √b

4. a/√b = a/√b x √b/√b = a√b / b

5. (a + √b)(a - √b) = a² + a√b - a√b - (√b)² = a² - b

6. to rationalise the denominator, you multiply the top and bottom by the denominator

7. simplify surds by finding two numbers that multiply together to get your surd, one of which is a square number ( if it is a square route ), and then turn the square number into a normal number.

   • eg √20 = √4 x √5 = 2 x √5 = 2√5