ShmoopTube

Where Monty Python meets your 10th grade teacher.

Search Thousands of Shmoop Videos

GED Math 3.4 Expression and Equations 311 Views


Share It!


Description:

GED Math: Expression and Equations Drill 3, Problem 4. What are the roots of the quadratic equation?

Language:
English Language

Transcript

00:00

Thank you We sneak in and here's your smoke to

00:05

your brought to you by the golden rule which is

00:08

basically don't ever try to take a leper con school

00:11

Really not worth getting away from my goal All right

00:14

one of the routes of the quadratic equation x squared

00:16

plus seven x minus thirty equals forty eight and hear

00:19

the potential answers it is All right very matthew question

00:28

here We need to solve this quadratic x squared plus

00:32

seven x minus thirty equals forty eight and figure out

00:35

what the roots would be All right Well here's the

00:37

golden rule first solving quadratic always said one side of

00:40

the equation equal to zero before trying to factor well

00:44

to get one side to be zero We're going to

00:46

need to subtract forty eight from both sides and just

00:49

rewrite The equation is x squared plus seven x minus

00:51

seventy eight equals zero and now we need to get

00:55

two factors of negative seventy eight that add up to

00:57

seven Like what Times what would be seventy eight But

01:02

then if you also added to the seven and we

01:04

could start thinking well alright we think it could be

01:06

like thirty nine times to could it be three times

01:10

thirteen and no that's It can't break down thirteen any

01:15

further So the factors are two three and thirteen is

01:21

any combination of those make seven So the answer is

01:24

no not really But if we multiply the two and

01:27

the three together we get six and six from thirteen

01:32

is seven We need this To be negative seventy eight

01:35

So we'll have tohave one minus sign in there when

01:38

we're factoring and we're gonna wind up with x minus

01:41

six times x plus thirteen that if we multiplied check

01:46

ourselves except axes x squared than outside him outside his

01:50

x times thirteen thirteen x minus six x yeah thirteen

01:54

minus six is seven and then negative six times thirteen

01:57

Yep that gets us our negative seventy eight But now

02:00

that we're done factoring one of the routes well x

02:03

minus six zero so one factor has got to be

02:05

six and x plus thirteen's gotta be zero so yep

02:10

negative thirteen is the other one so our answers eh

02:14

You can have the answer but don't touch my gold

Related Videos

SAT Math 4.1 Algebra and Functions
1196 Views

SAT Math 4.1 Algebra and Functions

GED Math 5.5 Graphs and Functions
882 Views

GED Math: Graphs and Functions Drill 5, Problem 5. What is the value of a?

GED Math 1.1 Measurement
327 Views

GED Math: Measurement Drill 1, Problem 1. The area, in square inches, of the shaded region where the two rectangles overlap is...what?

GED Math 1.1 Graphs and Functions
11928 Views

GED Math 1.1 Graphs and Functions. Which is the appropriate region of the coordinate plane?

GED Math 1.1 Expressions and Equations
878 Views

GED Math: Expression and Equations Drill 1, Problem 1. How much do the apples cost after tax?