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Numbers and Operations Videos 63 videos
SAT Math 1.1 Numbers and Operations. How many combinations of beverage and cereal can be made?
SAT Math: Numbers and Operations Drill 1, Problem 2. If the masterpiece will be worth $45,055 in five years, what is its worth now?
SAT Math 1.3 Numbers and Operations. x and y must be which of the following?
SAT Math: Solving a Rational Equation through Common Denominators 5 Views
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Description:
What are the value(s) of x in the rational equation above?
Transcript
- 00:00
Yeah Whoa Okay I say t mash bumpers and other
- 00:05
weird equation for you here We got this thing and
- 00:08
one of racks wanted Teo name exposed to what The
- 00:11
values of acts in the rational equation above All right
- 00:17
So rational meaning X is not zero nor negative too
Full Transcript
- 00:20
Right Okay well let's think about this Would it be
- 00:22
irrational to a skip this rational equation question Probably because
- 00:27
it's much simpler than it looks Let's start by writing
- 00:29
every term with a common denominator because fractions loved to
- 00:32
get closer together So let's think about this We're going
- 00:35
to multiply out X plus two on both sides of
- 00:38
this thing and then x over exxon this thing and
- 00:41
then x over X I guess Yeah on this thing
- 00:43
So that gives us as the denominator extends quantity X
- 00:46
plus two and the numerator looks like this So then
- 00:49
we have What is that X plus two plus Acts
- 00:53
over X 20 exposed to and and that equals negative
- 00:56
two acts over this thing and then we can rewrite
- 00:58
it again as two x plus two over x ten
- 01:02
twenty flew and then equals negative to activate All right
- 01:05
so a few operations with fractions and our question becomes
- 01:08
so much easier to deal with The denominators of these
- 01:11
two fractions are exactly the same So the numerator Sze
- 01:13
must equal as well It's a big trick there You
- 01:16
have to know you crossed this whole bottom thing out
- 01:19
and it gives you two X plus two equals negative
- 01:21
to X Well then four Acts If you add 2
- 01:24
exit both sides and subtract two from their equals native
- 01:27
to so X is negative to force or negative one
- 01:31
half Well it's like he's our answer but because this
- 01:33
is a rational equation we need to check that B
- 01:36
is not an extraneous solution i e One that does
- 01:39
not make the denominator equal to zero We're looking at
- 01:42
the original equation We can see that if Acts were
- 01:44
equal 2:0 or negative too those would be extraneous Welby
- 01:48
doesn't cause any problems so well that's our answer You
- 01:51
got to be careful in these because they'll throw curveballs
- 01:53
like at you all day long If you divide by
- 01:55
zero it has to be undefined If it's not well 00:01:58.49 --> [endTime] it's probably wrong
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