Question #55f2d

2 Answers
Sep 9, 2016

lim_(xrarr2) (x^3-3x^2+4)/(x^3-x^2-8x+12) = color(green)(3/5)

Explanation:

The problem is that both:
color(white)("XXX")x^3-3x^2+4 and
color(white)("XXX")x^3-x^2-8x+12
are equal to 0 if x=2

...but this means that both of these expressions are divisible by (x-2)

and using either synthetic or long division we can get:
color(white)("XXX")(x^3-3x^2+4)/(x^3-x^2-8x+12)=(cancel(""(x-2))(x^2-x-2))/(cancel(""(x-2))(x^2+x-6)

Unfortunately both
color(white)("XXX")x^2-x-2 and
color(white)("XXX")x^2+x-6
are also both equal to 0 if x=2

...but (again) this means that both of these expressions are divisible by (x-2)

and we can get
color(white)("XXX")(x^2-x-2)/(x^2+x-6)=(cancel(""(x-2))(x+1))/(cancel(""(x-2))(x+3))

So we have
color(white)("XXX")lim_(xrarr2) (x^3-3x^2+4)/(x^3-x^2-8x+12) =lim_(xrarr2) (x+1)/(x+3)

color(white)("XXXXXXXXXXXXXXXXX")=(2+1)/(2+3)=3/5

Sep 9, 2016

I found: 3/5

Explanation:

Try this:
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