Which of the following statements must be true about the polynomial function f(x)? If 1+ the sqrt of 13 is a root of f(x), then
-1- the sqrt of 13 is also a root of f(x). If 1 + 13i is a root of f(x), then 1 – 13i is also a root of f(x). If 13 is a root of f(x), then –13 is also a root of f(x). If –13 + i is a root of f(x), then 13 + i is also a root of f(x).
The correct answer is: if is a root of , then is also a root of .
In fact, every polynomial has real and/or complex solutions. If all solutions are real, we're good. But if not all of them are real, then the complex ones come in couple of conjugate solutions. Since and are conjugate complex numbers, if one of them is a solution, the other must be as well.
I'll give a practice problem to help explain it a bit better.
Here, let's try to solve 45% of of 60.
First, we convert the percentage into a decimal. To turn any percentage into a decimal you move the point two spaces to the left.
That means 45% as a decimal is .45.
Next, we multiply our number, 60, by the decimal .45.
60×.45=27.
That means 45% of 60 is 27.
To sum it all up, you have to get the percentage, move the decimal point two spaces to the left, and multiply it by the number you were trying to find the percentage of.