Ask question

Ask question

All categories

3 years ago

13

A student does the following to simplify a rational expression. Is the work correct? Explain any errors and how you would correc

t them.
$\frac{3x + x {}^{2} }{3x} = 1 + x {}^{2}$

1 answer:

Doss [256]3 years ago

3 0

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

Explanation:

The given rational expression is,

$\frac{3x+x^2}{3x}$

Since 3x is the common denominator of 3x and $x^2$ .

It can be written as,

$\frac{3x+x^2}{3x}=\frac{3x}{3x}+ \frac{x^2}{3x}$

Simplify the above expression,

$\frac{3x+x^2}{3x}=1+ \frac{x}{3}$

So the correct value of the expression is, $1+ \frac{x}{3}$ .

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

$\frac{3x+x^2}{3x} =1+x^2$

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

$\frac{3x+x^2}{3x} =\frac{3x}{3x}+x^2=1+x^2$

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

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

You might be interested in

Hi, Could anyone help me with my homework

tatiyna

Answer:

$\hookrightarrow \sf x^6+24x^5+240x^4+1280x^3+3840x^2+6144x+4096$

solving steps:

$\rightarrow \sf (x + 4)^6$

$\bold{rewrite \ the \ following}$

$\rightarrow \sf (x + 4)^2 (x + 4)^2 (x + 4)^2$

$\bold {formula \ used : \sf (x+a)^2 = (x^2 + 2xa + a^2)}$

$\rightarrow \sf (x^2 + 8x+16) (x^2 + 8x+16) (x^2 + 8x+16)$

$\bold{simplify \ by \ removing \ parenthesis}$

$\rightarrow \sf (x^4 +8x^3 + 16x^2 + 8x^3 +64x^2 + 128x+16x^2+128x+256 ) (x^2 + 8x+16)$

$\bold{basic \ addition \ of \ integers }$

$\rightarrow \sf (x^4+16x^3+96x^2+256x+256) (x^2 + 8x+16)$

$\bold{remove \ parenthesis}$

$\rightarrow \sf (x^6 + 16x^5 + 96x^4 + 256x^3 + 256x^2 + 8x^6 + 128x^4 + 768x^3 + 2048x^2 + 2048 + 16x^4 + 256x^3 + 1536x^2 + 4096x + 4096)$

$\bold {final \ answer:}$

$\rightarrow \sf x^6+24x^5+240x^4+1280x^3+3840x^2+6144x+4096$

8 0

2 years ago

X-25/14=6/7 find the solution

Lubov Fominskaja [6]

$x= \frac{6}{7} + \frac{25}{14} = \frac{12+25}{14} = \frac{37}{14}$

4 0

3 years ago

Simplify the expression

kow [346]

Answer:

<h3> f(x) = 5x² + 2x</h3><h3> g(x) = 6x - 6</h3>

Step-by-step explanation:

$\dfrac{5x^3-8x^2-4x}{6x^2-18x+12}\\\\6(x^2-3x+2)\ne0\ \iff\ x=\frac{3\pm\sqrt{9-8}}{2}\ne0\ \iff\ x\ne2\ \wedge\ x\ne1\\\\\\\dfrac{5x^3-8x^2-4x}{6x^2-18x+12}=\dfrac{x(5x^2-8x-4)}{6(x^2-3x+2)}=\dfrac{x(5x^2-10x+2x-4)}{6(x^2-2x-x+2)}=\\\\\\=\dfrac{x[5x(x-2)+2(x-2)]}{6[x(x-2)-(x-2)]} =\dfrac{x(x-2)(5x+2)}{6(x-2)(x-1)}=\dfrac{x(5x+2)}{6(x-1)}=\dfrac{5x^2+2x}{6x-6}\\\\\\f(x)=5x^2+2x\\\\g(x)=6x-6$

4 0

3 years ago

A custom rectangular tabletop has a length that is twice it’s width, and the tabletop measures 76 inches on its diagonal. What a

Sunny_sXe [5.5K]

Answer:

<em>The dimensions of the tabletop: Length= 67.976... inches and Width= 33.988... inches and the perimeter will be 203.929... inches.</em>

Step-by-step explanation:

Suppose, the width of the rectangular tabletop is $x$ inch.

As the tabletop has a length that is twice it’s width, so the length will be: $2x$ inch.

The tabletop measures 76 inches on its diagonal.

<u>Formula for length of diagonal of rectangle</u>: $d=\sqrt{l^2+w^2}$

So, the equation will be..........

$76=\sqrt{(2x)^2+ x^2}\\ \\ 76=\sqrt{4x^2+x^2} \\ \\ 76=\sqrt{5x^2} \\ \\ 5x^2= 76^2= 5776\\ \\ x^2= \frac{5776}{5}=1155.2 \\ \\ x= \sqrt{1155.2} =33.988...$

Thus, the width of the tabletop is 33.988... inches and the length will be: (2×33.988...) = 67.976... inches.

The perimeter will be: 2(33.988...+ 67.976...) inches = 203.929... inches.

5 0

3 years ago

100 pints help would be greatly appreciated

Veronika [31]

Answer:

(4, -2) (see attached)

Step-by-step explanation:

Vector addition on a graph is accomplished by placing the tail of one vector on the nose of the one it is being added to. The negative of a vector is in the direction opposite to the original.

__

<h3>vector components</h3>

The components of the vectors are ...

u = (1, -2)

v = (-6, -6)

Then the components of the vector sum are ...

2u -1/3v = 2(1, -2) -1/3(-6, -6) = (2 +6/3, -4 +6/3)

2u -1/3v = (4, -2)

<h3>graphically</h3>

The sum is shown graphically in the attachment. Vector u is added to itself by putting a copy at the end of the original. Then the nose of the second vector is at 2u.

One-third of vector v is subtracted by adding a vector to 2u that is 1/3 the length of v, and in the opposite direction. The nose of this added vector is the resultant: 2u-1/3v.

The resultant is in red in the attachment.

5 0

2 years ago