Help please - Algebra

11 Plus Maths – Preparation and Information

Moderators: Section Moderators, Forum Moderators

11 Plus Mocks - Practise the real exam experience - Book Now
Guest

Help please - Algebra

Post by Guest »

Hi

My son is stuck on the following and I can't help !

5h - 5 = 4h + 7

and

7t + 11 = 6t + 3

Please can someone help ?

Many thanks :)
chad
Posts: 1647
Joined: Tue Dec 13, 2005 1:49 pm
Location: berkshire

Post by chad »

What you do to one side you must do to the other...the aim is to get all the x's and all the numbers together.


5h - 5 = 4h + 7
5h =4h + 7+ 5 (add 5 to each side)
5h - 4h = 7 + 5 (subtract 4h from each side)
h = 12

7t + 11 = 6t + 3

7t - 6t + 11 = 3 ( subtract 6h from each side)

7t - 6t = 3 -11 (subtract 11 from each side)

t = -8
SunlampVexesEel
Posts: 1245
Joined: Fri Jul 06, 2007 9:31 pm

Re: Help please - Algebra

Post by SunlampVexesEel »

Anonymous wrote:Hi

My son is stuck on the following and I can't help !

5h - 5 = 4h + 7

and

7t + 11 = 6t + 3

Please can someone help ?

Many thanks :)
Imagine some scales. The = is in the middle of the scales.

5h - 5 = 4h + 7

to keep the scales balanced always perform the same operation to both sides

Subtract 4h from both sides

h - 5 = 7

add 5 to both sides

h = 12


and...

7t + 11 = 6t + 3

Subtract 6t from both sides

t + 11 = 3

subtract 11 from both sides

t = -8

Once you get the hang of it you can imagine things moving to the other side and the sign changing...

Regards
SVE
Animis opibusque parati
naga
Posts: 14
Joined: Thu Oct 11, 2007 12:51 pm

Re: Help please - Algebra

Post by naga »

Anonymous wrote:Hi

My son is stuck on the following and I can't help !

5h - 5 = 4h + 7

and

7t + 11 = 6t + 3

Please can someone help ?

Many thanks :)
If u bring the right hand side h to left hand side,
then 5h-4h-5=7 ,then the equation will become
h-5=7

then

u know h= 5+7=12 after bringing -5 to the right side.

2) 7t+11=6t+3


the same rule,

7t-6t+11=3,

t+11=3,

t=3-11=-8

t=-8. hope this helps
Guest

Post by Guest »

Thanks for the replies...

We are getting there slowly,my son has gone from never having done any algebra in the Junior school to this homework.

Please could someone help with this one ?

3x + 5 = 4x - 2

I never did algebra at school so I'm no help to my son at all !

Many thanks.
Guest

Post by Guest »

Anonymous wrote:Thanks for the replies...

We are getting there slowly,my son has gone from never having done any algebra in the Junior school to this homework.

Please could someone help with this one ?

3x + 5 = 4x - 2

I never did algebra at school so I'm no help to my son at all !

Many thanks.
Always do the same thing to both sides of the equals to simplify equation.

Subtract 3x

5=x-2

Add 2

x=7

OR

Subtract 4x

-x+5=-2

Subtract 5

-x=-7

x=7 (essentially adding x and 7 to each side)
Guest

Solving equations

Post by Guest »

When asked to solve an equation, what it is really asking you to find is the numerical value for x, which when you substitute into both sides of the equation, both sides equal each other.
Ultimately, you have to gather all the unknown terms on one side of the equation and all the numbers on the other. To do this you add/subtract/multiply/divide etc depending on the level of difficulty and "whatever you do to one side you have to do to the other". I have to admit when I introduce this I draw pictures!!!!! and we answer it visually first then set about sorting out the algebra.
so 3x + 5 = 4x - 2 Look at the quantities of x, which is the larger? Ok, then how do you reduce 3x back to zero? well subtract 3x, but "whatever you do to one side you have to do to the other."
(-3x) 5 = x - 2 (-3x)
(+2) 7 = x (+2) the rationale here being "how do you get -2 back to zero? By adding 2.....
Al this sounds very lengthy but I'm attempting to put into words what I say to my teaching groups. Visual, verbal, explaining what you are doing each time in a few examples, then let the students go for it themselves. I always always encourage my students to write in brackets what they are doing.
Hope this helps in a small way. Trying to write what you say when you teach is very very long-winded!!!!! Sorry.
Yours C.
BTW this is how it would look on paper:
3x +5 = 4x - 2
(-3x) 5 = x - 2 (-3x)
(+2) 7 = x (+2)
Guest

Post by Guest »

Thankyou all very much for your help,the homework is done, he is happy and I am very relieved . This is just the first term of year 7,I dread to think how we will manage in later years !
Bewildered
Posts: 1806
Joined: Mon Feb 20, 2006 2:29 pm
Location: Berkshire

Post by Bewildered »

Having been taught a different method of doing algebra to the above when I was at school, does anyone know if this is now the standard method used at secondary, or do they progress onto something different?

Thanks

BW
chad
Posts: 1647
Joined: Tue Dec 13, 2005 1:49 pm
Location: berkshire

Post by chad »

I would recommend the Usborne Dictionary of Maths for any parent with a child in senior school....excellent diagrams, explanations and examples written in a way that I can understand and my son can understand. This has the added benefit of showing the accepted way of approaching the maths curriculum. One of the best £8's I have spent. My son, now in Y8, still uses it if he is not sure of a subject. :D
Post Reply
11 Plus Platform - Online Practice Makes Perfect - Try Now