ShmoopTube
Where Monty Python meets your 10th grade teacher.
Search Thousands of Shmoop Videos
TSI Math: Solving a Quadratic Equation through Grouping 2 Views
Share It!
Description:
Which of the following values is a root of the equation 10x² = 37x – 7?
- Test Prep / TSI
- Intermediate Algebra and Functions / Quadratic and Other Polynomial Expressions, Equations, and Functions
- TSI / TSI Math
- TSI / TSI Mathematics
- TSI Mathematics / Intermediate Algebra and Functions
- Intermediate Algebra and Functions / Quadratic and Other Polynomial Expressions, Equations, and Functions
- Test Prep / TSI
- TSI Math / Intermediate Algebra and Functions
Transcript
- 00:03
Okay yes i'm ass movers More quadratic ce in polly
- 00:06
and no meals here Which of the following values is
- 00:09
a root of the equation Ten x squared equals thirty
- 00:13
seven x minus seven Okay when you see these things
- 00:18
immediately quad ratify them so we're going to get negative
Full Transcript
- 00:22
Ten x squared plus thirty seven x minus seven is
- 00:24
zero See we've zero fight it then we could use
- 00:27
the quadratic formula here but well we'll solve this equation
- 00:31
by grouping instead It's probably easier when the coefficient of
- 00:34
x squared isn't one like here It's ten or negative
- 00:37
ten Actually the first step is to multiply the coefficient
- 00:39
of x squared by the constant term Well here we
- 00:42
get negative ten times Negative seven which makes positive seventy
- 00:47
Now we need to think of two factors of this
- 00:49
result here for seventy which add up to thirty seven
- 00:52
So what could it be Yeah two times thirty five
- 00:56
is seventy and two plus thirty five is thirty seven
- 01:00
So pretty easy so we can rewrite This is thirty
- 01:02
seven x thing here is to Acts plus 35 acts
- 01:06
that'll help on the fact arising thing here So we're
- 01:09
then gonna factor to acts from the group to simplify
- 01:12
things a tad and we get well to x out
- 01:15
here that multiplies through the negative five x plus one
- 01:19
and then we've got the multiplying by negative seven times
- 01:24
the quantity negative five expose one equal zero we've got
- 01:26
negative five x plus one inside each parentheses here is
- 01:30
very clever very hard to dio Very hard to recognize
- 01:32
but hopefully you got it Okay so yes are factoring
- 01:35
was successful and now we're going to factor out the
- 01:38
negative five x plus one So we get that over
- 01:41
here on the left and then we're going to multiply
- 01:42
it by two x minus seven to get zero Well
- 01:45
the roots can be found by setting each of the
- 01:48
expressions in parentheses equals zero and just solving for x
- 01:51
Right So that gets us negative Five Acts plus 1
- 01:56
equals 0 and while we can subtract one from both
- 02:00
sides there we get negative five x equals negative one
- 02:03
Divide both sides by negative five and we get x
- 02:06
equals a fifth So whoa hold up That happens to
- 02:09
be be so we've technically found our answer However never
- 02:13
let it be said we don't finish what we start
- 02:15
to find the other route I'll do the same with
- 02:17
two x minus seven thereby adding seven on both sides
- 02:20
we get to act Sequel seven in the nexus seven
- 02:22
abs This is a positive value not the negative values
- 02:26
seen in negative seven halves there So give it up
- 02:30
either So the answer is b it's one fifth and 00:02:32.903 --> [endTime] that is in fact a route of that equation
Up Next
Which is the best way to revise and combine sentences 1 and 2?
Related Videos
Where would the following sentence best be placed?
Which of the following is best to insert at the beginning of sentence 8?
Which is the best location for sentence 9?
Which of the following sentences is best to insert between sentences 11 and 12?