Question

Solve the equation. Check for extraneous solutions. 2|7-7x|=2x+4

Answer 1

Divide both sides by 2 first.

Answer 2

Show me what you come up with after that step I just told you.

Answer 3

7-7x=x+4?

Answer 4

why is the +4 still there when you divided both sides by 2.

Answer 5

?*

Answer 6

no, dont forget to divide everything!

Answer 7

so that side would be x+2 then

Answer 8

Correct.

Answer 9

Now when you get rid of the absolute value signs, you get two solution sets.

Answer 10

\[7-7x=x+2\]
or
\[7-7x=-(x+2)\]

Answer 11

Do you understand that or have you learnt that in class?

Answer 12

yeah I get that

Answer 13

Okay solve for x as normal for the first equation first.

Answer 14

Tell me what you get for x in the first equation.

Answer 15

wait wouldn`t the x`s cancel each other out? I`m so lost

Answer 16

You don't know how to solve this simple equation?
\[7-7x=x+2\]

Answer 17

No need to be mean we are all at diffrent levels of math here/

Answer 18

I'm asking her so then if she says yes, I'm going show her step by step.

Answer 19

No I don`t know how

Answer 20

Okay. Then Imagine x is the number 1.

Answer 21

and 7x is the number 7

Answer 22

Don't look at the pronumeral. Just look at the number beside it.

Answer 23

here is what you do from here on out.
minus 2 from both sides. 5-7x=x
Then add 7x to both sides.
-> 5=8x
divide by 8 both sides -> 5/8=x

Answer 24

@AIK Good job. I'm showing her step by step so she can understand.

Answer 25

So it would be 5/8

Answer 26

Do you know how to get that? Because if you just say "Yes, I know how to get it", then it's your fault if you get a really low mark in maths.

Answer 27

@Brittanyy! Do you know what "collecting like terms" is?

Answer 28

Yes I really do get it. You minus 2 from both sides to cancel the 2 on the right side and get x by itself then add 7x to both sides to get x on one side then divide by 8 to find x. Thanks so much!

Answer 29

Then do the second equation by yourself and tell me the answer for the second one.

Answer 30

If you understand this, then I'm sure you can finish off the second equation and tell me the answer.

Answer 31

@Brittanyy! Do you have the answer now?

Answer 32

Remember everything in a equation is related.
So x+2=2 -> you can not only minus 2 from one side, you have to from both
x+2-2=2-2 -> x=0
It is the same for division and multiplication
->like terms is gathering all numbers of a same kind together.
It is to make the equation easier by getting a number=variable
P.S when doing l7-7xl do not forget to do both of the possible equations and check the answers

Answer 33

Ah god, I have a feeling that you're giving answers and then letting the receiver fail in a maths exam later on. But who am I to judge because I'm not going to be the one who's going to fail.