Find the polynomial of lowest degree with only real coefficients and having the given zeros. -7i and square root of 2

x³ - (√2)x² + 49x - 49√2

Step-by-step explanation:

If one root is -7i, another root must be 7i.  You can't just have one root with i.  The other roos is √2, so there are 3 roots.  

x = -7i       is one root,

   (x + 7i) = 0    is the factor

x = 7i       is one root

  (x - 7i) = 0     is the factor

x = √2      is one root

    (x - √2) = 0   is the factor

So the factors are...

(x + 7i)(x - 7i)(x - √2) = 0

Multiply these out to find the polynomial...

(x + 7i)(x - 7i) =  x² + 7i - 7i - 49i²

Which simplifies to

  x² - 49i²        since i² = -1 , we have

    x² - 49(-1)  

      x² + 49

Now we have...

(x² + 49)(x - √2) = 0

Now foil this out...

 x²(x) - x²(-√2) + 49(x) + 49(-√2) = 0

     x³ + (√2)x² + 49x - 49√2

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.