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TSI Math: Using Prime Factorization to Find Cubed Roots 14 Views
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Description:
What value when cubed is equal to -216x⁵?
- Intermediate Algebra and Functions / Expressions, Equations, and Functions Involving Powers, Roots, and Radicals
- Test Prep / TSI
- TSI / TSI Math
- TSI / TSI Mathematics
- Intermediate Algebra and Functions / Expressions, Equations, and Functions Involving Powers, Roots, and Radicals
- TSI Mathematics / Intermediate Algebra and Functions
- Test Prep / TSI
- TSI Math / Intermediate Algebra and Functions
Transcript
- 00:03
Okay radical Tsc shmoop er's Here we go I got
- 00:06
another question for you What value when cubed is equal
- 00:10
to negative to sixteen times x to the fifth So
- 00:17
how do we get there How do we get to
- 00:19
the cube root of this thing Well we separate the
Full Transcript
- 00:21
factors under the cube so it looks like this We've
- 00:24
got the cube root of negative to sixty next to
- 00:26
the fifth which is the same as the cube root
- 00:29
of negative one times cube root of to sixteen You
- 00:32
should recognize that to sixteen Number because it's a special
- 00:36
number We've got them the cube root of x to
- 00:38
the fifth as its multiple can there So that's what
- 00:41
It's gonna look like this Negative one to sixteen Fifty
- 00:44
Yeah Now it's Time to find each of these three
- 00:47
cube roots Slow and steady wins The race was going
- 00:49
to come one at a time Here we go Cube
- 00:51
root of negative one is negative one right Because negative
- 00:54
one two The third powers Negative one All right Once
- 00:56
that's done we'll turn our attention to the cube root
- 00:58
of to sixteen Start by finding the prime factors of
- 01:02
two sixteen there and so whole lot of threes And
- 01:04
you know this because you could add two plus one
- 01:06
plus six which gets you nine and that's evenly Divisible
- 01:10
by three So you know three is going to be
- 01:12
one of those factors right Well to do so we
- 01:14
keep dividing out Smalls primes is possible Is shown here
- 01:18
we got two Sixteen equals two times one Oh eh
- 01:20
with vehicles two times two times fifty for which equals
- 01:23
two times two times two two twenty seven which equals
- 01:26
all this stuff right here at the end of the
- 01:28
day It's two cubed times three cubed that's it Then
- 01:31
we separate the factors and that allows us to take
- 01:34
the cube roots here So cube root of to sixteen
- 01:37
is the cube root of two to the third times
- 01:40
three to the third which is same as the cube
- 01:43
root of two to the third which is just too
- 01:46
in the cube root of three to the third which
- 01:48
is just three So the freakin answer is six You
- 01:50
could have gotten there by knowing that six times six
- 01:53
is thirty six I'm six is two Sixteen that's What
- 01:56
we mean by it's one of those special numbers You'll
- 01:58
see that a lot of tests So you may I
- 01:59
just want to kind of note that in your brain
- 02:01
All right well specifically then we go to take the
- 02:04
cube root of x to the fifth by factoring out
- 02:06
an x cube there that's the same as x to
- 02:08
the three plus two which is same as x to
- 02:11
the third times x to the squared or to the
- 02:13
second power there orjust x squared So once again separate
- 02:16
the factors under the cube root symbol Here we've got
- 02:18
the cube root of exit third times x squared that
- 02:22
gives us the cube root of x cubed times the
- 02:24
cube root of x squared which equals x times the
- 02:27
cube root of x squared right there So we found
- 02:30
each of the three cube roots that we originally set
- 02:33
out to find So it's time to finish the problem
- 02:35
Put them all together and get your simplify on right
- 02:38
so cube root of negative one time's cube root of
- 02:42
to sixteen there times cube root of x fifth is
- 02:44
the same as native One time six times acts times
- 02:48
cube root of x squared which same as negative six
- 02:51
x times the cube root of x squared wow that
- 02:54
was ugly but were done And the answer is v 00:02:57.46 --> [endTime] and let's Just move on
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