Find the value of 'a' in the equation a³+a = 130

Answer :

We have   : a³  +  a =  130   ,

And we know 

2³  =   8

3³ =  27

4³ =  64

5³ =  125

6³ = 216 

So, we can say that value of a is less than 6  

SO, We check for a  =  4 , we get

4³ +  4  =  64  + 4  =  68

Now We check for a  =  5 , we get

5³ +  5  =  125  + 5  =  130

SO,

a  =  5                                                                                       ( Ans )