Question

Solve for x.

-ax + 2b > 8
http://i.imgur.com/FLuD7Cl.png

Answer 1

first subtract 2b from both sides and what do you have?

Answer 2

-ax > 8 - 2b

Answer 3

-ax > -2b + 8 I mean.

Answer 4

well actually we have a problem

Answer 5

without knowing if a is negative of positive or 0 we cant go any further without cases

Answer 6

So its B.

Answer 7

Since dividing both sides by -a.

Answer 8

I am saying that the question is a bad question and you should tell your teacher that you cant solve it without knowing if a is negative, positive, or 0

Answer 9

a is negative.

Answer 10

you say that because you see a - sign right?

Answer 11

Mhm.

Answer 12

well what is -(-3)?

Answer 13

But its not like that.

Answer 14

so if a=-3

-a = 3 > 0

Answer 15

ok let us assume -a is negative number

Answer 16

Plus all of them have -a, except D which is wrong since it has -2b - 8

Answer 17

nope

Answer 18

because notice they remove the negative from the bottom, that will change the top

Answer 19

ok lets assume its negative

then you have -ax> 8-2b

right?

Answer 20

Yes

Answer 21

now we divide by -a and since we are assuming its negative, we flip the sign

\(x< \frac{8-2b}{-a}\)

you with me?

Answer 22

oh ok, then yes its c, I thought it has an a on the bottom

Answer 23

err b

Answer 24

It is C?

Answer 25

Oh

Answer 26

But you should tell your teacher that this is a bad question. They will be happy if you understand why.

notice that they did not tell you anything about a, so a could be any real number

what if we choose a=-3

-(-3)x+2b>8
we subtract the 2b

-(-3)x>8-2b
this is the same as
3x>8-2b

now we divide by 3 and the sign never gets flipped

Answer 27

so depending on the sign of a we get different answers

also, a could be equal to 0

so we have -0x+2b>8
2b>8

now we cant even solve for x

this problem is bad on many levels and you should complain if you are paying for the class.