# Rationalise the denominator of 1/((8 + 5√2))

Last updated at Sept. 11, 2020 by Teachoo

Last updated at Sept. 11, 2020 by Teachoo

Transcript

Rationalise the denominator of 1/((8 + 5√2)) We have 1/((8 + 5√2)) = 1/((8 + 5√2)) × ((8 − 5√2))/((8 − 5√2)) = ((8 − 5√2))/((8)^2 − (5√2)^2 ) = ((8 − 5√2))/(64 − 50) = ((𝟖 − 𝟓√𝟐))/𝟏𝟒

Rationalising

Rationalising denominator of irrational number

Add (3√2+7√3) and (√2−5√3)

Divide 5√11 by 3√33

Multiply 2√15 by 7√5

Simplify (√5+√7)^2

Simplify (√4−√13)(√4+√13)

Simplify (9−√3)(9+√3)

Simplify (3√5−5√2)(4√5+3√2)

Rationalise the denominator of 8/√7

Rationalise the denominator of 1/((8 + 5√2)) You are here

Multiple Choice Questions - Chapter 1 Class 9 Maths

Simplify (7√3)/(√10 + √3)−(2√5)/(√6 + √5)−(3√2)/(√15 + 3√2)

If a and b are rational numbers and (√11 − √7)/(√11 + √7) = a – b√77, find the value of a and b

Example 17

Example 18

Find the values of a and b if (7 + 3√5)/(3 + √5) – (7 − 3√5)/(3 − √5) = a+√5 b

Ex 1.5,5 Important

If x = 1/(2 − √3), find the value of x^3 − 2x^2 − 7x + 5

Example 19 Important

If a = 5 + 2√6 and b = 1/a, then what will be the value of a^2+b^2 ?

Example 20

Chapter 1 Class 9 Number Systems

Concept wise

- Rational numbers - Definition
- Finding rational number between two numbers
- Irrational Numbers
- Simplifying real numbers
- Rationalising
- Laws of exponents
- Finding decimal expansion
- Expressing decimal in p/q
- Classifiying rational/irrational
- Finding irrational numbers b/w two numbers
- Real numbers on a number line

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.