Evaluate the polynomial for x = 4. x^3 - 5x^2 + x


Evaluate the polynomial for {eq}\, x = 4 {/eq}.

{eq}x^3 - 5x^2 + x {/eq}


Evaluating an expression for a specific value of the variable is done by finding the numerical value of the expression when the variable takes that particular value. This numerical value is found by substituting the variable with the value it is taking in the expression.

Answer and Explanation:

Evaluating the polynomial for x=4 means finding the value that the polynomial will take when the x terms in it have been replaced by 4. Once the x have been replaced with 4, we calculate the value of the polynomial by performing the mathematical operations required.

$$\begin{align} &x^3 - 5x^2 + x\\ &\text{Replacing x with 4,}\\ \Rightarrow &4^3 - 5*4^2 + 4&&&&\left [ ax=a*x \right ]\\ =&64-80+4\\ =&-12 \end{align} $$

Learn more about this topic:

Evaluating Simple Algebraic Expressions

from ELM: CSU Math Study Guide

Chapter 6 / Lesson 3

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