I need help i dont get it
2 answers:
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Answer:
it must also have the root : - 6i
Step-by-step explanation:
If a polynomial is expressed with real coefficients (which must be the case if it is a function f(x) in the Real coordinate system), then if it has a complex root "a+bi", it must also have for root the conjugate of that complex root.
This is because in order to render a polynomial with Real coefficients, the binomial factor (x - (a+bi)) originated using the complex root would be able to eliminate the imaginary unit, only when multiplied by the binomial factor generated by its conjugate: (x - (a-bi)). This is shown below:
where the imaginary unit has disappeared, making the expression real.
So in our case, a+bi is -6i (real part a=0, and imaginary part b=-6)
Then, the conjugate of this root would be: +6i, giving us the other complex root that also may be present in the real polynomial we are dealing with.
Answer:
Height of fir tree = 9 meters
height of pine tree= 12 meters
Step-by-step explanation:
The combined height of one fir tree and one pine tree is 21 meters. The height of 4 fir trees stacked on top of each other is 24 meters taller than one pine tree.
Let x be the height of fir tree and y be the height of pine tree
Subtract x from both sides
height of 4 fir trees = pine tree +24
Substitute 21-x or y in the above equation
Add x on both sides
Divide by 5 on both sides
x=9
Now plug in 9 for x and find out y
y=12
Height of fir tree = 9 meters
height of pine tree= 12 meters