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## Help! Year 8 Maths question makes no sense to anyone in our house!

(39 Posts)
TaudrieTattoo Sun 22-Sep-13 21:49:22

DP and I have four degrees between us, but this is impossible.

Anyone good at Maths?

The question is: Multiplying a number by three and adding four is equal to subtracting the number from 28. What is the number? Let the number be x.

You have to express it as an equation then solve it.

I got as far as 28-x = 3x x 4 but then ground to a halt.

It's mathematical bollocks to me.

Can anyone help my poor DS?

fuzzpig Sun 22-Sep-13 21:52:25

X is 6

Sun 22-Sep-13 21:52:42

Here you go...

3x + 4 = 28 - x

4x + 4 = 28

(subtract 4 from both sides)

4x = 24

(divide both sides by 4)

x = 6

TaudrieTattoo Sun 22-Sep-13 21:53:05

I love you.

Could you express that as an equation please?

MrsRajeshKoothrappali Sun 22-Sep-13 21:53:07

I'd love to help but embarrassed myself massively during the last MN Child's Maths Homework Debacle.

However, I will give it a go.

RoonilWazlibWuvsHermyown Sun 22-Sep-13 21:53:22

28 - x = 3x + 4
28 = 3x + 4 + x
28 = 4x + 4
28 - 4 = 4x
24 = 4x
6 = x
x = 6

RoonilWazlibWuvsHermyown Sun 22-Sep-13 21:53:45

Dammit, slow typing!

fuzzpig Sun 22-Sep-13 21:54:02

Where you wrote it above you've got an x instead of + at the end

28 - x = 3x + 4
24 - x = 3x
24 = 4x
6 = x

ClayDavis Sun 22-Sep-13 21:54:56

I think that should be 28-x=3x + 4.

First get rid of the x on the left by adding x to both sides
28=4x+4

Then get rid of the 4 on the right by subtracting 4 from both sides to give
24=4x

Finally divide both sides by 4 to get x.

ClayDavis Sun 22-Sep-13 21:55:34

x posts with everybody.

JoinTheDots Sun 22-Sep-13 21:55:53

You need:

3x+4=28-x

minus 4 from each side

24-x=3x

24=4x

x=24/4

x=6

Theas18 Sun 22-Sep-13 21:56:13

That isn't hard is it. what part did you/your child not grasp? I guess that are supposed to work it out as roo as done rather than just Trying a couple of numbers that i thought would work and seeing it they did, which was what I did isn't what they want!

ScramblyEgg Sun 22-Sep-13 21:57:01

You've got the initial equation wrong, it's plus 4 not times 4.

28 - x = 3x + 4

add x to both parts of the equation

28 = 3x + x + 4

subtract 4 from both parts of the equation

28 -4 = 3x + x

24 = 4x

x = 6

I think that's right, it's decades since I did any real maths

ScramblyEgg Sun 22-Sep-13 21:57:32

Oh, I'm so slow!

TaudrieTattoo Sun 22-Sep-13 21:57:49

Thank you!

Our brains just don't do numbers!

UnicornsNotRiddenByGrownUps Sun 22-Sep-13 22:00:34

This thread is like watching black magic......

ClayDavis Sun 22-Sep-13 22:00:50

If he really doesn't understand it, it would be better to hand it in undone or having done as much as he can rather than done by some one else.

RoonilWazlibWuvsHermyown Sun 22-Sep-13 22:01:07

notthefirstagainstthewall Sun 22-Sep-13 22:06:45

OMG that's Year 8 not A'level ?!!!

It's not going to be pretty in our house in 2 years time...

notthefirstagainstthewall Sun 22-Sep-13 22:08:37

And there was a reply in just 3 minutes...[awe emoticon]

SwedishEdith Sun 22-Sep-13 22:17:16

@ the breezy That isn't hard is it.

Sun 22-Sep-13 22:25:28

It's just your basic equation with X on both sides.

There's 2 elements that are being tested.

1) Can he make an expression using X?

e.g. I am X years old. Sue is 5 years older. Express Sue's age in terms of X.

2) Can he rearrange equations to find X?

Simple ones: 5X + 2 = 32

Harder ones: 5X + 2 = 32 - X

It might be useful to see which ones he finds hard.

soontobeburns Sun 22-Sep-13 22:31:44

What??? I just did my maths gcse 5 years ago and I passed. This makes no sense!

Fucking x as long as you can do mental maths this isnt needed.

That makes no sense to me yet aptitude questions I pass with flying colours.

HappyHugs Sun 22-Sep-13 22:51:34

I honestly dont think that's particularly difficult. I did my gcse maths in 1991 and remembered how to approach it from then; and that would've been among the easier algebra we tackled. What age is year 8? All different in N.Ireland...

ClayDavis Sun 22-Sep-13 22:56:22

12-13, Happy. Obviously, if you don't know how to do it, it's hard, but I agree it is among the easier algebra.

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