The function is: f(x) = x^3 - 5x^2 - x + 6
Substitution value x = 2
2 | 1 -5 -1 6 write down the coefficients of the polynomial
| 2 drop the 1st coefft below the line.
============ now multiply it by the subst value
1 place result under 2nd coefft and add them.
2 | 1 -5 -1 6
| 2
============
1 -3 multiply the -3 by the subst value.
2 | 1 -5 -1 6
| 2 -6 place result under 3rd coefft and add them.
============
1 -3
2 | 1 -5 -1 6
| 2 -6
============
1 -3 -7 multiply the -7 by the subst value.
2 | 1 -5 -1 6
| 2 -6 -14 place result under 4th coefft and add them
============
1 -3 -7
2 | 1 -5 -1 6
| 2 -6 -14
============
1 -3 -7 -8 This last result, -8, is the answer.
Answer: f(2) = -8
Substitution value x = -1
-1| 1 -5 -1 6 write down the coefficients of the polynomial
| -1 drop the 1st coefft below the line.
============ now multiply it by the subst value
1 place result under 2nd coefft and add them.
-1| 1 -5 -1 6
| -1
============
1 -6 multiply the -6 by the subst value.
-1| 1 -5 -1 6
| -1 6 place result under 3rd coefft and add them.
============
1 -6
-1| 1 -5 -1 6
| -1 6
============
1 -6 5 multiply the 5 by the subst value.
-1| 1 -5 -1 6
| -1 -6 -5 place result under 4th coefft and add them
============
1 -6
-1| 1 -5 -1 6
| -1 -6 -5
============
1 -6 -7 1 This last result, 1, is the answer.
Answer: f(-1) = 1