Math problem (year 8 level, should be easy)

[gifi4]

Well on my text book, the exercise is 7.4 (not relevant but w/e) and the question is "Form an equivalent equation to each of the following by performing the operation given in brackets."

Now the first question.

"x-4=1 (+7)"

Note: the "x" is a pronumeral.

I'm expected to hand this in tomorrow and I have no idea what to do so if someone can help me by explaining how to do it, I will be incredibly grateful.

Thanks in advance.

 

[nick22]

Just add 7 at both sides of the 'is equal to' sign...

 

[Scott-105]

As the poster above said, add 7 to each side.

The new equation would be: x + 3 = 8

 

[Attila13]

x=5

 

[Thoob]

Yeah, I think he would have preferred the answer over a month ago, when he asked. Nice bump.

 

[Attila13]

Yeah, I think he would have preferred the answer over a month ago, when he asked. Nice bump.

Sorry

I wasn't registered back then!

 

[Thoob]

Yeah, I think he would have preferred the answer over a month ago, when he asked. Nice bump.

Sorry

I wasn't registered back then!

In fact, from a glance at your profile, you registered a week before then. FAIL.

 

[basher11]

>_> you registered on 10/11/10.

the topic was started on 10/18/10

 

[mameks]

Nice bump ;3
At least you can do algebra, even though you can't do dates

 

[Attila13]

Never mind... I was in a rush

It's true that I registered on the 11th October, but then I wasn't very familiar with the forums...
I don't mind you can laugh at me as much as you want, I don't care...

We're here to make friends...(I sure am

)

P.S.
@ shlong
almost 1000 post dude!

 

[mameks]

Never mind... I was in a rush

It's true that I registered on the 11th October, but then I wasn't very familiar with the forums...
I don't mind you can laugh at me as much as you want, I don't care...

We're here to make friends...(I sure am

)

P.S.
@ shlong
almost 1000 post dude!

I know

Not that I'm going to spam any of it though :3

 

[The Pi]

What's the proof of 1+1=2?

 

[_Chaz_]

What's the proof of 1+1=2?

1+1=2, because I told it to.

 

[Attila13]

What's the proof of 1+1=2?

1+1=2, because I told it to.

Makes sense!

 

[mcp2]

What's the proof of 1+1=2?

There isn't!

 

[hetoan2]

actually i think there is a proof for 1+1=2 which is around 500 pages iirc.

it's easier to prove that .999... = 1

 

[tj_cool]

(1 + 1) x 0 = 2 x 0
-> 1 + 1 = 2
Q.E.D.

 

[The Pi]

The actual proof is proving that 2>1 then doing something else which I can't remember.
I have it in my notes somewhere it's 1 page not 500

 

[ProtoKun7]

(1 + 1) x 0 = 2 x 0
-> 1 + 1 = 2
Q.E.D.

Now to prove that the universe has no inhabitants.

 

[KingdomBlade]

The proof starts from the Peano Postulates, which define the natural
numbers N. N is the smallest set satisfying these postulates:

P1. 1 is in N.
P2. If x is in N, then its "successor" x' is in N.
P3. There is no x such that x' = 1.
P4. If x isn't 1, then there is a y in N such that y' = x.
P5. If S is a subset of N, 1 is in S, and the implication
(x in S => x' in S) holds, then S = N.

Then you have to define addition recursively:
Def: Let a and b be in N. If b = 1, then define a + b = a'
(using P1 and P2). If b isn't 1, then let c' = b, with c in N
(using P4), and define a + b = (a + c)'.

Then you have to define 2:
Def: 2 = 1'

2 is in N by P1, P2, and the definition of 2.

Theorem: 1 + 1 = 2

Proof: Use the first part of the definition of + with a = b = 1.
Then 1 + 1 = 1' = 2 Q.E.D.

Note: There is an alternate formulation of the Peano Postulates which
replaces 1 with 0 in P1, P3, P4, and P5. Then you have to change the
definition of addition to this:
Def: Let a and b be in N. If b = 0, then define a + b = a.
If b isn't 0, then let c' = b, with c in N, and define
a + b = (a + c)'.

You also have to define 1 = 0', and 2 = 1'. Then the proof of the
Theorem above is a little different:

Proof: Use the second part of the definition of + first:
1 + 1 = (1 + 0)'
Now use the first part of the definition of + on the sum in
parentheses: 1 + 1 = (1)' = 1' = 2 Q.E.D.

There's your proof.

(1 + 1) x 0 = 2 x 0
-> 1 + 1 = 2
Q.E.D.

So that means that:

(685944.543 + 1043255252.435252) X 0 = 2 X 0
-> 685944.543 + 1043255252.435252 = 2

I highly doubt it.