Simplify (3√5−5√2)(4√5+3√2)
Last updated at Dec. 16, 2024 by Teachoo
Rationalising
Rationalising denominator of irrational number
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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
Transcript
Simplify (3√5−5√2)(4√5+3√2) (3√5−5√2)(4√5+3√2) = 3√5(4√5+3√2) − 5√2 (4√5+3√2) = 3√5 × 4√5+3√5 × 3√2 − 5√2 × 4√5−5√2 × 3√2 = 12 × 5+9√10 − 20√10 − 15 × 2 = 30−11√10 Rationalising the denominator For number 2/(4 − √5) Rationalising 2/(4 − √5) = 2(4 + √5)/(𝟒^𝟐 − (√𝟓)^𝟐 ) = 2/(4 − √5) × (𝟒 + √𝟓)/(𝟒 + √𝟓) = 2(4 + √5)/(16 − 5)
