ShmoopTube

00:00

Thank you We sneak And here's your smoked you sure

00:05

brought to you by dead birds And you thought your

00:09

flight was delayed All right if four x squared plus

00:13

six x plus thirty five equals sixteen x squared plus

00:16

seven x What is one value of x All right

00:20

near the potential answers All right well we've got two

00:25

ways to do this thing Isn't it nice having options

00:28

One way would be to plug in each of the

00:30

four answer choices one at a time until we find

00:32

one that works But way just did the plug and

00:35

chug method for last problem we solved and we want

00:37

to mix things up a bit Do things the hard

00:39

way this time Don't give us that look you know

00:41

keep you sharp Okay so the first thing we want

00:44

to do is combined like terms We got a couple

00:46

of x squared here so let's subtract four x squared

00:49

from both sides Then we have a couple of ex

00:52

terms that will subtract six acts from both sides to

00:54

get those over to the right as well And finally

00:57

will subtract thirty five from both sides And now we've

00:59

got zero equals twelve x squared plus x minus thirty

01:03

five Much cleaner looking Almost looks pretty enough to kiss

01:07

on the mouth there That headline All right so now

01:10

we've got this polynomial but we still need to solve

01:13

for x timeto factor We know that we can get

01:16

to twelve x squared By multiplying twelve x pi x

01:19

six x by two ex or for x by three

01:23

x And because our last term is negative thirty five

01:26

it's probably going to be some combination of a seven

01:29

and a half five Well after a little finagle ng

01:31

we realised that four x times five is twenty x

01:34

and three x times seven is twenty one x which

01:37

is a difference of one x and that's the middle

01:40

of our pollen O'neill right on the right track to

01:43

get everything would work out perfectly We'll need to put

01:45

four x plus seven in one set of parentheses and

01:48

three x minus five and the other let's Double check

01:51

to make sure we did that right for x times

01:53

Three axes twelve x squared All good there Three x

01:56

times seven is twenty one x and for x times

01:58

negative five is twenty Ex those cancel out toe one

02:02

x So it's still looking promising and finally seven times

02:06

negative five is negative Thirty five loot We got it

02:09

Now we can set each of those equal to zero

02:12

and go home from there So for x plus seven

02:15

equals zero We can Subtract seven from each side to

02:18

get for x equals negative seven then divide both sides

02:23

by four to get x equals negative seven Force well

02:27

but that's not one of our option that's not freak

02:30

out question did ask us to find just one value

02:32

of Acts So hopefully this other 1 works out well

02:35

Three x minus five equals zero at five Both sides

02:38

to get three x equals five then divide both sides

02:41

by three To get x equals five thirds and bingo

02:45

option c Now if you're really found that painful feel

02:48

free to use the plug and chug method next time

02:50

you get a similar problem But aren't you glad you

02:52

know what the senior group looks like in case you're

02:55

ever interested in a leisurely stroll All right point taken

Full Transcript