Given the expression:
![\displaystyle \large{ \sqrt[3]{ - 125} }](https://tex.z-dn.net/?f=%20%5Cdisplaystyle%20%5Clarge%7B%20%5Csqrt%5B3%5D%7B%20-%20125%7D%20%7D)
Definition:
![\displaystyle \large{ y = \begin{cases} \pm \sqrt[n]{x} \longrightarrow n = (2,4,6,8,...) \: \: (x \geqslant 0) \\ \sqrt[n]{x}\longrightarrow n = (1,3,5,7,...) \: \: (x \in \R) \end{cases}}](https://tex.z-dn.net/?f=%20%5Cdisplaystyle%20%5Clarge%7B%20y%20%20%3D%20%5Cbegin%7Bcases%7D%20%20%20%5Cpm%20%5Csqrt%5Bn%5D%7Bx%7D%20%20%5Clongrightarrow%20n%20%20%3D%20%282%2C4%2C6%2C8%2C...%29%20%20%5C%3A%20%20%5C%3A%20%28x%20%5Cgeqslant%200%29%20%5C%5C%20%20%20%5Csqrt%5Bn%5D%7Bx%7D%5Clongrightarrow%20n%20%3D%20%281%2C3%2C5%2C7%2C...%29%20%5C%3A%20%20%5C%3A%20%28x%20%5Cin%20%5CR%29%20%5Cend%7Bcases%7D%7D)
First, factor the -125. -125 comes from (-5)×(-5)×(-5) or (-5)^3.
![\displaystyle \large{ \sqrt[3]{ ( - 5) \times ( - 5) \times ( - 5)} }](https://tex.z-dn.net/?f=%20%5Cdisplaystyle%20%5Clarge%7B%20%5Csqrt%5B3%5D%7B%20%28%20-%205%29%20%5Ctimes%20%28%20-%205%29%20%5Ctimes%20%28%20-%205%29%7D%20%7D)
Because if (-5)^2 = 25 then 25×(-5) again will be -125.
Since this is the cube root, we have to pull out 3 terms in one. There are 3 fives that we can take off and therefore,
We need to 'standardise' the value of X = 14.4 by first calculating the z-score then look up on the z-table for the p-value (which is the probability)
The formula for z-score:
z = (X-μ) ÷ σ
Where
X = 14.4
μ = the average mean = 18
σ = the standard deviation = 1.2
Substitute these value into the formula
z-score = (14.4 - 18) ÷ 1..2 = -3
We are looking to find P(Z < -3)
The table attached conveniently gives us the value of P(Z < -3) but if you only have the table that read p-value to the left of positive z, then the trick is to do:
1 - P(Z<3)
From the table
P(Z < -3) = 0.0013
The probability of the runners have times less than 14.4 secs is 0.0013 = 0.13%
10 less than 'x' may be represented algebraically as the quantity (x - 10) .
There's no way to calculate its numerical value without knowing the value of 'x'.
Answer:
100
Step-by-step explanation:
