Question

Solve for x: |2x + 6| − 4 = 20

x = 9 and x = 11

x = −9 and x = 15

x = 9 and x = −15

No solution

Answer 1

2x+6-4=20 and 2x+6-4=-20 right?

Answer 2

Wait no. Put 4 on right side?

Answer 3

@Nnesha

Answer 4

first move everything from left to right side except the absolute bar

Answer 5

okay, so how do I do that?

Answer 6

do what ?

Answer 7

do you mean how to move -4 to the right side ?

Answer 8

Move everything.

Answer 9

Oh, so we just move -4?

Answer 10

there is only -4
how would you cancel out -4 from left side ?

Answer 11

You can't.

Answer 12

yes but which action would take subtract/add/multiply or divide both sides by -4 ?

Answer 13

you*

Answer 14

So 20-4

Answer 15

Subtract?

Answer 16

hmm no it's already negative at left side so do opposite of subtraction

Answer 17

Oh, addition. Okay.

Answer 18

right! add 4 both sides then you can separate that into 2 equations

Answer 19

\[2x+6-4+4=20+4?\]

Answer 20

don't forget the absolute bar \[\left| 2x+6 \right| -4+4=20 +4\]

Answer 21

Oh, okay. So then I solve right?

Answer 22

2x+6=24

Answer 23

and 2nd equation ?

Answer 24

2x+6-4+4=-20+4?

Answer 25

no first to get rid of everything except the absolute bar
you got \[\left| 2x+6 \right|=24\]
now separate the absolute bar into two equation

Answer 26

How?

Answer 27

just like we did on the previous post
\[\rm \left| a+b \right| = c ~~~~~~~\left| a+b\right| =- c \]

Answer 28

2x+6=-20

Answer 29

how did you get -20?

Answer 30

Woops.

Answer 31

remember ) first we need absolute bar itself on the left side
2nd) then we can spllit absolute into the equation with each sign (plus/negative)

Answer 32

Isn't it -20?

Answer 33

no.
what did you get when u added 4 both sides ?

Answer 34

24

Answer 35

right so it should be 24 not 20

Answer 36

so, 2x+6=-24?

Answer 37

right

Answer 38

2x=-30

Answer 39

x=-15

Answer 40

good

Answer 41

So, 9 and -15?

Answer 42

did you get 9 for first equation ?

Answer 43

Yes.

Answer 44

ok then. right!

Answer 45

Thanks! :)

Answer 46

np