Question icon
Grade 12th passAlgebra

Please prove it by full explain ation gvsnnbdb hdbdnh

Question image for Please prove it by full explain ation gvsnnbdb hd
Profile image of ARUN KUMAR
4 Years agoGrade 12th pass
Answers icon

1 Answer

Profile image of Harsh Tiwari
4 Years ago
Given,
LCM and HCF of two numbers are the same.
Let the two rational numbers be x and y.
Given,
LCM(x,y)=HCF(x,y)
Let,
LCM(x,y)=HCF(x,y)=k, for some value k.
HCF being the highest common factor is always a factor of both the numbers.
Therefore the numbers can be written as multiples of HCF.
That is,
 x=ka , for some natural number a
 y=kb , for some natural number b
Now, since the product of two numbers is equal to the product of their LCM and HCF, we have
x×y=LCM(x,y)×HCF(x,y)
 
Substituting the values for x, y, their LCM and HCF,
ka×kb=k×k
⇒k2ab=k2
Cancelling k2 from both sides,
ab=1
⇒a=1,b=1 ( since a and b are natural numbers).
Substituting these we get x and y as
⇒x=ka=k×1=k⇒y=kb=k×1=k
⇒x=y=k
Therefore, the two numbers are the equal