Simplify
\[x ^{2}-9/x ^{2}+5x+6 * 1/x+3 \]
\[\frac{ x^2 - 9 }{ x^2 + 5x + \frac{ 6*1 }{ x+3 } } \] is this right?
or is it more like this? \[\frac{ x^2−9 }{ x^2+5x+6 } \times \frac{ 1 }{ x+3 }\] ?? @charlieberzak
ummm
i got three answers :D
1 1/x+2 x-3/(x+2)(x+3)
yeah but what's the question?
above
\[x^2 - \frac{ 9 }{ x^2 } + 5x + 6\times \frac{ 1 }{ x+3 }\] ???
which one?
here: http://curriculum.kcdistancelearning.com/courses/ALG1x-HS-A06/b/Exams/9Quiz2/9Quiz2_q6.gif
ok so as it's multiply the 2 fractions, simply multiply straight across ie numerator x numerator and denominator by denominator ie 1/6 * 4 / 10 = (1*4) / (6 * 10) = 4 / 60
then simplify the single fraction by removing factors from top and bottom
Nooooo. DO NOT multiply first! Factor the num'r and den'r of the first rational expression, first. ALWAYS better to factor and reduce first, THEN multiply. This goes for fractions as well as rational expressions, but expecially here, taking that product first will be one HOT MESS. Factor first and things will cancel. You'll be left with something very simple when you multiply.
\[\Large \dfrac{ x^2−9 }{ x^2+5x+6 } \times \dfrac{ 1 }{ x+3 }\] That first numerator is a difference of squares, so it factors: \(\large a^2-b^2=(a-b)(a+b)\) The first den'r also factors into the product of 2 binomials ("undo" the FOIL).
And in fact, in your answer choices everything is in factored form, or reduces completely, so you won't even really "multiply" when you multiply.
\[\frac{ x^2-9 }{ (x+3) (x^2+5x+6) } = \frac{ x^2-9 }{ (x+3) (x+2) (x+3) }\] ... wasn;t that hard and it still dosent simplify ...?
x^2 - 9 = (x+3) (x-3) yeah?
so u can remove one of those as a factor if u like @charlieberzak
lol ok, you didn't really "multiply" in that den'r, you wrote it all as a product in one rational expression, but when you told him to "multiply across" I thought you were telling him to actually TAKE THE PRODUCT of that trinomial with the binomial in the den'r (that would, indeed, be a hot mess). What you did in the den'r is exactly what I was telling him to do - factor. And yes, it is important that the num'r also factors. And you don't "remove one of those as a factor if u like". The problem is to "SIMPLIFY" the expression, so you MUST reduce all common factors. What you are left with is one of the answer choices.
true
\[(x ^{2}-9) \div (x^2+5x+6)(x+3)=(x+3)(x-3)\div(x+2)(x+3)(x+3) = (x-3)\div((x+2)(x+3)\]
is it 1?
Read what's above, @charlieberzak. @jack1 did pretty much the whole problem for you, just reduce the common factors. What's left?? \[\frac{ x^2-9 }{ (x+3) (x^2+5x+6) }= \frac{(x+3)(x-3) }{ (x+3) (x+2) (x+3) }\]
THe only way it would be =1 is if ALL the factors in num'r and den'r cancelled.
(x+3) (x-3)??
??? For what? That isn't even one of your answer choices. That's the num'r, before you reduce.
What does this reduce to?? \(\Large \dfrac{(x+3)(x-3) }{ (x+3) (x+2) (x+3) }\)
o so its would have to be the third choice
Yes. but you really need to understand how to factor these, yourself.
x-3 -------- (x+2)(x+3)
\[a^2-b^2=(a+b)(a-b) \] so by applying it to \[x^2-9=x^2-3^2\]
we get (x+3)(x-3)
dude, appreciate the sentiment but maybe @DebbieG is a better choice for that, considering who stayed around and helped you vs who went a looked at pictures of cats instead (sorry they're just hilarious sometime tho) ;D
@charlieberzak ^^
:D
No worries @jack1.... :) And who doesn't like looking at pictures of cats?? :)
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