Question

On dividing both the numerator and the denominator of 20a^2b/5ab^2 by ? The result is 4a/b

Answer 1

5ab is the correct answer

Answer 2

`5ab`

Explanation:

Given rational expression,

`(20a^2b)/(5ab^2)`

Let x be the expression by which on dividing both the numerator and the denominator the result is
`(4a)/(b)`

That is,

`((20a^2b)/(x))/((5ab^2)/(x))=(4a)/(b)`

By comparing numerators,

`(20a^2b)/(x)=4a`

`20a^2b=4ax` ( By cross multiplication )

`\implies x = (20a^2b)/(4a)=5a^(2-1)b^2=5ab`

Note : We can get the answer by comparing denominators.