Answer:
The required polynomial is f(x)=
Step-by-step explanation:
Given that polynomial is passing through points (-1,-1) (0,7) ( 1,9) and (2,17)
Let, The required polynomial be f(x)=
For point (-1,-1)
f(x)=
f(-1)=
(-1)a+b-c+d=(-1) Equation 1
For point (0,7)
f(x)=
f(0)=
d=7 Equation 2
For point ( 1,9)
f(x)=
f(1)=
a+b+c+d=9 Equation 3
For point (2,17)
f(x)=
f(2)=
8a+4b+2c+d=17 Equation 4
Replacing value of d of equation 2 in equation 1,3,4
For equation 1:
(-1)a+b-c+d=(-1)
(-1)a+b-c=(-8)
For equation 3:
a+b+c+d=9
a+b+c=2
For equation 4:
8a+4b+2c+d=17
8a+4b+2c=10
Now,
On adding equation 1 and 3
For equation 1: (-1)a+b-c=(-8)
For equation 3: a+b+c=2
((-1)a+b-c)+(a+b+c)=(-8)+2
2b=(-6)
b=(-3)
Replacing value of b in equation 1 and 4:
For equation 1: (-1)a+b-c=(-8)
(-1)a+(-3)-c=(-8)
(-1)a-c=(-5) Equation 4
For equation 4: 8a+4b+2c=10
8a+4b+2c=10
8a+4(-3)+2c=10
8a+2c=22 Equation 5
For value of a and c:
Equation 4 can be write as
(-1)a-c=(-5)
a+c=5
a=5-c
Replacing value of a in equation 5
8a+2c=22
8(5-c)+2c=22
40-8c+2c=22
-6c=-18
c=3
So,
a=5-c=5-3=2
a=2
Thus,
The value of
a=2, b=(-3), c=3 and d=7
The required polynomial is
f(x)=
f(x)=
