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OpenStudy (anonymous):
=5(a-4)/(a-4)
**(a-4) reduces, which leaves with : 5
OpenStudy (anonymous):
so, it wants the restrictions of the variables so would it be \[a\]
OpenStudy (anonymous):
a cannot equal 5?
jimthompson5910 (jim_thompson5910):
what value makes the denominator a+4 equal to 0 ?
OpenStudy (anonymous):
-4?
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jimthompson5910 (jim_thompson5910):
so \[\Large a \neq -4\]
to avoid division by zero
OpenStudy (anonymous):
Oops I though it was reducing question
jimthompson5910 (jim_thompson5910):
that reads "a is not equal to -4"
OpenStudy (anonymous):
okay, well.. for the next one it's 2x-3² divided by 5x³ and it says that a cannot equal 0, but how do i solve the problem to get the answer?
jimthompson5910 (jim_thompson5910):
same question: what makes the denominator 0?
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jimthompson5910 (jim_thompson5910):
to answer that, you set the denominator equal to zero and solve for x
OpenStudy (anonymous):
so... 1/5?
jimthompson5910 (jim_thompson5910):
no
jimthompson5910 (jim_thompson5910):
5x^3 = 0
x^3 = 0
x = cube root of 0
x = 0
jimthompson5910 (jim_thompson5910):
you can check it by plugging x =0 into 5x^3
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OpenStudy (anonymous):
that's just 0 though right...?
jimthompson5910 (jim_thompson5910):
so that's why x cannot equal 0
to avoid division by zero in "2x-3² divided by 5x³ "
OpenStudy (anonymous):
but how do i solve the problem? it's either 1/5, 1/5x, 1/5x², or 2-3x/5x²
jimthompson5910 (jim_thompson5910):
oh you just want to simplify
jimthompson5910 (jim_thompson5910):
one sec
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OpenStudy (anonymous):
alright, thanks
jimthompson5910 (jim_thompson5910):
The original problem is
\[\Large \frac{2x - 3x^2}{5x^3}\]
right?
OpenStudy (anonymous):
yes sir
jimthompson5910 (jim_thompson5910):
what can you factor out of the numerator?
OpenStudy (anonymous):
ummmmm........ 3x².?
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jimthompson5910 (jim_thompson5910):
what do 2x and 3x^2 have in common? what factors?
OpenStudy (anonymous):
oh, 6?
jimthompson5910 (jim_thompson5910):
6 is the LCM of 2 and 3, I'm looking for the GCF
jimthompson5910 (jim_thompson5910):
2x has an x
3x^2 = 3*x*x
So they both have 1 x
That's the GCF
jimthompson5910 (jim_thompson5910):
when you factor x from the numerator, you get?
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OpenStudy (anonymous):
1?
jimthompson5910 (jim_thompson5910):
2x - 3x^2
x*2 - x*3x
what's the next step? We want to factor out x
OpenStudy (anonymous):
divide by 1x?
jimthompson5910 (jim_thompson5910):
yes, and have an x outside like this
x(2 - 3x)
jimthompson5910 (jim_thompson5910):
if you were to distribute that x back in, you'll get 2x - 3x^2 again
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jimthompson5910 (jim_thompson5910):
so we factor the numerator and denominator and then cancel to get
\[\Large \frac{2x - 3x^2}{5x^3}\]
\[\Large \frac{x(2 - 3x)}{5x^3}\]
\[\Large \frac{x(2 - 3x)}{x*5x^2}\]
\[\large \frac{\color{red}{\cancel{\color{black}{x}}}(2 - 3x)}{\color{red}{\cancel{\color{black}{x}}}*5x^2}\]
\[\Large \frac{2 - 3x}{5x^2}\]