Question

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

Answer 1

Answer:

The number is 2.26

Step-by-step 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 = $\frac{-b\pm \sqrt{b^{2}-4\times a\times c}}{2\times a}$

Or, x = $\frac{+\pm \sqrt{-1^{2}-4\times 18\times -90}}{2\times 18}$

Or, x = $\frac{1\pm \sqrt{6481}}{36}$

So, x = $\frac{1\pm 80.50}{36}$

∴  x  = $\frac{81.50}{36}$ = 2.26

Hence The number is 2.26  Answer