Question

4.2x - 3 = .5 (8.4x + 6) and 2/3x + 1 = 2/3x -1
Just lead me in the right direction please mates? I don't need the answer, just to know how to do these.

Answer 1

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Answer 2

is it 2 different questions? or a system of equations?

Answer 3

two different

Answer 4

you have 3 basic algebra properties to play with: identites, inverses, and distribution/factoring

Answer 5

4.2x - 3 = .5 (8.4x + 6)

distribution: a(b+c) = ab+ac
factoring: ab+ac = a(b+c)

one idea is to distribute to start with. what do we get as a result?

Answer 6

Well, I'm not very good a t math. But the way I was told was to do something like
4.2x - 3 = .5(8.4x + 6)
4.2x - 3 = 4.2x + 3
-4.2x -3 = -4.2x +3
And this is where I get lost cause I either get -6 or +6

Answer 7

Same goes for the second, I get either -2 or +2

Answer 8

Neither make sense when I try to check.

Answer 9

.2x - 3 = 4.2x + 3 is fine to play with

lets start getting the x parts all by themselves. -3 + ? = 0

Answer 10

+3?

Answer 11

teh 4 didnt copy over, but yes .... so lets add 3 to each side

4.2x - 3 = 4.2x + 3
+3 +3
-----------------
4.2x = 4.2x + 6

is there any number that you can think of that is 6 more than itself?

Answer 12

Wait, but aren't we supposed to do subtract x from both side? I know I'm supposed to get x all by itself, but isn't that when there are two variables, I have to subtract/add from one?

Answer 13

you can if you need to, but math is logical

Answer 14

if we subtract 4.2x from each side we get: 0 = 6 which is not a logical construction

Answer 15

this means that there is no solution that will make it true

Answer 16

Mmm, I guess that makes sense.

Answer 17

2/3x + 1 = 2/3x -1

is x on the bottom or beside the 2/3 ?

Answer 18

either way, this is the same logic. 2/3x is just some number

add 1 to each side ... is there a number that is equal to 2 more than itself?

Answer 19

or rather, when does 0=2?

Answer 20

0 never equals something. Wait, hold on, I'm trying to figure out your smartness first. Lemme try answering the first one with this new info. I'll give you what I got. gimem about a 2 minutes.

Answer 21

if my internet holds up, ill be around :)

Answer 22

okay so, I'm still stuck on the first question. 4.2x = 4.2x + 3
Am I on the right track?

Answer 23

+6 not +3 but yeah

Answer 24

then I subtract X?

Answer 25

we have 4.2x on each side, to keep things equal, what we do to one side we do to the other.

if we remove 4.2x from one side, we remove it from the other.

subtracting x is doable, but doesnt really lead us anyplace useful

Answer 26

4.2x = 4.2x + 3

4.2x-x = 4.2x-x + 3

3.2 = 3.2x + 3

Answer 27

i spose it gets rid of 1x ... 3.2 more to go :)

Answer 28

So, then. I can't subtract x, cause then I won't have an x.

Answer 29

and i trust your smart enough to see thru the typos

Answer 30

you can subtract up to 4.2 xs after that there are no more that can be subtracted

Answer 31

4.2x = 4.2x + 6
-4.2x -4.2x
---------------
0x = 6

so we get to 0=6

Answer 32

SO, I was sorta right? 6 is the answer?

Answer 33

But when I try to check, substitution for 6, I get different answers.

Answer 34

6 isnt the answer, the answer is, what value of x makes: 0x = 6 true?

Answer 35

so, 0, times what, is equal to 6?

Answer 36

Argh! But 0 times anything is always 0.

Answer 37

I dun geeeet it. Should I go in for help period?

Answer 38

a math sentence can be as gibberish and meaningless as any other sentence.

when a math sentence is meaningless, or nonsensical, we conclude that there is no answer that will suffice.

Answer 39

0x = 6 has no solution.

Answer 40

therefore:

4.2x - 3 = .5 (8.4x + 6)

has no solution and is a nonsensical math sentence

Answer 41

geometrically, this represents 2 lines that never meet

Answer 42

Wait, is there an answer to the equations though?

Answer 43

the answer is that there is no solution to the equation

Answer 44

That's new. Kay thanks