<span>x² - 18x - 4 = ox² - 18x = 4x² - 18x + (18/2)² = 4 + (18/2)²x² - 18x + 81
</span>
I believe it’s 6
Hope this helps you :))
3 pipes take 12 hours
⇒ In 1 hour, the 3 pipes can fill 1/12 of the pool
2 of the pipes take 18 hours
⇒ in 1 hour, the 2 pipes can fill 1/18 of the pool
In 1 hour, the third pipe alone can fill :

Time needed :

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Answer: It will take 36 hours for the third pipe to fill the pool.----------------------------------------------------------------------------------------
Jus go a thru z and you’ll be fine
So what you're going to do is just multiply how you were normal to play multiply the numerator times the other numerator then multiply the denominator's and that should get you your answer and then you can try and simplify it by finding if it can be divided equally then see if it is bigger or smaller