Math Is Fun Forum

GeeGee

Member

Registered: 2008-09-27

Posts: 7

algebra and another problem

My daughter can't understand three questions in her homework can you help me so that I can help her? (She's English speaking in a Swiss school and the math teacher speaks no English)

1)   3a*4d*5c*7x=
2)   3a(7b-11b+15d)=
Can you tell me the answers and how to do these and maybe where I can look so my daughter can understand this type of problem?

3) 550+555+560 ..............................  1745+ 1750
We can see what is happening here but what sort of answer is the teacher looking for?

Mum to GG

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 46,457

Re: algebra and another problem

Dear Mum to GG,
the first two questions are relatively simple to answer:-
The numbers are called the constants nd the alphabets are called th variables.
All that has to be don is multiply all the constants, and then multiply a;; the variab;es, and finally multiply both the results.
An example of multiplying a constant and a variable is given below:-
2 x a = 2a

he first two solutions:-
(3*4*5*7)(a*d*c*x) = 420adcx

and in the second problem, multiply every ter, inide the brackets of the second part by the first part. You get

21ab -33ab +45ad.

Operations such as addution, subtrction, multiplication and division can be carried out if the constants are the same. Hence, the result cam be simlified as
-12ab+45ad.

The third question is sum of an Arithmetic Progression (You can view all the formulas relating to Arithmetic Progressions in 'Formulas' in the following thread, post #4.

The Sum is given by (a+l)n/2. Here a=550, l=1750, n=241, (i.e.1750-550)/5 + 1, therefore,
Sum=2300 x 241/2 = 1150 x 241 = 277150.

Howeer, this problem can also be solved by simplifying it into smaller problems.

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