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2 votes
Given the polynomial:

4
x
2

4
x
3
+
x
4
+
3
+
7
x


Evaluate the polynomial for x = -4

1 Answer

3 votes

Answer:

f(-4) = 39

Explanation:

4

x

2

4

x

3

+

x

4

+

3

+

7

Please write this all on one line: y = 4x^2 - 4x^3 + x^4 + 3 + 7x, and not vertically (as you have done). Note how I have used " ^ " to denote exponentiation.

We need to re arrange these terms in descending order by power of x:

y = 4x^2 - 4x^3 + x^4 + 3 + 7x => y = x^4 - 4x^3 + 4x^2 + 7x + 3.

We are to evaluate this polynomial for x = -4. Either replace each instance of x by -4 or use synthetic division (the remainder is the value of the polynomial at the given x-value.

At x = -4, we have y = (-4)^4 - 4(-4)^3 + 4(-4)^2 + 7(-4) + 3, or

y = 256 - 256 + 64 - 28 + 3, or 39 (answer)

User Dime
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