Question

The ratio of a number and 18 is equal to the difference of a number squared and 5

Answer 1

The number is 2.26

Explanation:

Let The given numbers be x

Now according to question :

x : 18 = x² - 5

I.e x = 18 × ( x² - 5 )

or, x = 18 × x² - 90

or, 18 x² - x - 90 = 0

Or, From quadratic equation , the value of x

x =
`\frac{-b\pm \sqrt{b^(2)-4* a* c}}{2* a}`

Or, x =
`\frac{+\pm \sqrt{-1^(2)-4* 18* -90}}{2* 18}`

Or, x =
`(1\pm √(6481))/(36)`

So, x =
`(1\pm 80.50)/(36)`

∴ x =
`(81.50)/(36)` = 2.26

Hence The number is 2.26 Answer