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A student does the following to simplify a rational expression. Is the work correct? Explain any errors and how you would correct them.
[tex] \frac{3x + x {}^{2} }{3x} = 1 + x {}^{2} [/tex]

Respuesta :

Answer: The work done by the student is not correct.

Explanation:

The given rational expression is,

[tex]\frac{3x+x^2}{3x}[/tex]

Since 3x is the common denominator of 3x and [tex]x^2[/tex].

It can be  written as,

[tex]\frac{3x+x^2}{3x}=\frac{3x}{3x}+ \frac{x^2}{3x}[/tex]

Simplify the above expression,

[tex]\frac{3x+x^2}{3x}=1+ \frac{x}{3}[/tex]

So the correct value of the expression is, [tex]1+ \frac{x}{3}[/tex].

According to the student the simplified form of the expression is,

[tex]\frac{3x+x^2}{3x} =1+x^2[/tex]

Which is not correct, because the student takes 3x in denominator of 3x only as shown below,

[tex]\frac{3x+x^2}{3x} =\frac{3x}{3x}+x^2=1+x^2[/tex]

The error made by the student is he didn't take 3x in the denominator of [tex]x^2[/tex].

Therefore, the simplified form written by the student is incorrect.