+0

# Solve for x: = 7.

0
372
10

Solve for x: = 7.

x = 3

x = 5

x = 6

x = 10

Guest Jul 21, 2014

#4
+91450
+5

I just gave you 3 points Mari,      I don't give points as easily as CPhill does.  I like people to really earn them.

You sort of did what CPhill did - I will try to explain.

$$\dfrac{(x+4)}{2}=7$$

You sort of said :  What divided by 2=7 and the answer is 14/2 is 7   This means that x+4=14

CPhill said : I want to get the x+4 on its own so how do I get rid of the 2  Umm I muliply by 2 but if I multiply the left side by 2 then i have to multiply the right side by2 as well.  This keeps the equation balanced!

$$\begin{array}{rlll} \frac{x+4}{2}&=&7\\\\ \frac{x+4}{2}\times 2&=&7\times 2\\\\ x+4&=&14\qquad \qquad \mbox{On the left the 2s cancel out, that is what CPhill did it for!}\\ \end{array}$$

Next you said :      What + 4=14 and the answer is obviously 10  SO    x=10

CPhill said:  x+4=14  I need the x by itself so how do I get rid of the +4 Umm  I know, I'll take it away (+4-4=0)

But if I take it away from the left side then I have to take it away from the right side too.  I have to keep the equation balanced!

x+4-4=14-4

x=10

See you sort of did the same thing only CPhill did it in a more formal way.

You need to learn how to do it the formal way or you will not be able to solve difficult equations later on.

ALWAYS REMEMBER - EQUATIONS ARE LIKE SCALES, THEY MUST STAY BALANCED AT ALL TIMES!

Melody  Jul 21, 2014
Sort:

#1
0

the problem is (x+4)/2=7

Guest Jul 21, 2014
#2
+468
+5

i dont really get how to do it. i just subsitute the numbers to see which one makes sense and i got 10

(10+4)/2=7

add 10+4 then divide it by 2 and it =7

14/2=7

mari379  Jul 21, 2014
#3
+80983
+5

But, what if we don't have those???

Let's see how to solve this....step by step...

(x+4)/2=7       multiply both sides by 2

x + 4  = 14      subtract 4 from both sides

x = 10

In upper level maths....you have to be able to solve "without the answers"........also, "plugging" in the answers takes too much time in a test situation !!!!

CPhill  Jul 21, 2014
#4
+91450
+5

I just gave you 3 points Mari,      I don't give points as easily as CPhill does.  I like people to really earn them.

You sort of did what CPhill did - I will try to explain.

$$\dfrac{(x+4)}{2}=7$$

You sort of said :  What divided by 2=7 and the answer is 14/2 is 7   This means that x+4=14

CPhill said : I want to get the x+4 on its own so how do I get rid of the 2  Umm I muliply by 2 but if I multiply the left side by 2 then i have to multiply the right side by2 as well.  This keeps the equation balanced!

$$\begin{array}{rlll} \frac{x+4}{2}&=&7\\\\ \frac{x+4}{2}\times 2&=&7\times 2\\\\ x+4&=&14\qquad \qquad \mbox{On the left the 2s cancel out, that is what CPhill did it for!}\\ \end{array}$$

Next you said :      What + 4=14 and the answer is obviously 10  SO    x=10

CPhill said:  x+4=14  I need the x by itself so how do I get rid of the +4 Umm  I know, I'll take it away (+4-4=0)

But if I take it away from the left side then I have to take it away from the right side too.  I have to keep the equation balanced!

x+4-4=14-4

x=10

See you sort of did the same thing only CPhill did it in a more formal way.

You need to learn how to do it the formal way or you will not be able to solve difficult equations later on.

ALWAYS REMEMBER - EQUATIONS ARE LIKE SCALES, THEY MUST STAY BALANCED AT ALL TIMES!

Melody  Jul 21, 2014
#5
+468
0

thank you melody! awesome and thanks for explaining it to me :)

mari379  Jul 21, 2014
#6
+80983
0

Yeah....be careful, mari379........Melody is a "meanie".......(LOL!!!)

CPhill  Jul 21, 2014
#7
+91450
0

YES

When I was Queen Guinevere I would behead my unruly subjects!

And, now that I am a dinosaur I eat them for breakfast!

So you better tread VERY carefully.  lol.

Melody  Jul 21, 2014
#8
+80983
0

Don't believe her for a minute, mari379.......her "bark" is worse than her "bite".....she's a "softy"....at heart.......

CPhill  Jul 21, 2014
#9
+11757
0

Yes CPhill your right!these kinda people are really very soft of heart!

I wonder , Zegroes is Godzilla and Godzilla is much more than dinosaur so it means that Godzilla is much more soft of heart than dinosaur!

A new secret of POOR Zeg-ROSE has been revealed!

rosala  Jul 21, 2014
#10
+91450
0

Sorry Chris

I didn't realise that it was a multiple choice answer. But it doesn't matter, my logic still holds.

And what do you mean

"My bark is worse than my bite" ?

Got you bluffed.  Lol.

Anyway Mari it had been good to see you on the forum with the rest of CPhill's "Rat Pack".

Melody  Jul 21, 2014

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