Question 977710: find a polynomial of the specified degree:
degree 4, zeros:-5,0,5,7
P(x)=
Answer by Edwin McCravy(20064) (Show Source):
You can put this solution on YOUR website! find a polynomial of the specified degree:
degree 4, zeros:-5,0,5,7
P(x)=
----------------
1. Put x= before each zero:
x=-5; x=0, x=5, x=7
2. Get 0 on the right of each of the 4 equations:
x+5=0; x=0; x-5=0; x-7=0
3. Indicate that the multiplication (product) of all the left sides equals
the multiplication (product) of all the 0's on the right side, which is just
0.
(x+5)x(x-5)(x-7) = 0
4. Do the multiplication:
To make the mutiplication easier put the x third
(x+5)(x-5)x(x-7) = 0
Multiply the first two that are conjugates (x+5)(x-5)
and distribute the x into the (x-7).
(x²-25)(x²-7x) = 0
Now just use FOIL
x4-7x3-25x2+175x = 0
5. The polynomial P(x) equals the left side of that polynomial equation:
P(x) = x4-7x3-25x2+175x
[Be sure not to put "= 0" after it, for P(x) does not necessarily equal to
0. P(x) only equals 0 when x equals to one of the 4 given zeros.]
Edwin
|
|
|