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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

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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