im a new user in this forum .. and i need a help .. please help me .. i have a doubt in maths ....

3x-2 (x-3)=12 .. what is the number ?????????????

please help me .. its soo urgent

i 'll be back

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- Feb 18th 2013, 07:03 AMarshiar8hello guysss peep in for more
im a new user in this forum .. and i need a help .. please help me .. i have a doubt in maths ....

3x-2 (x-3)=12 .. what is the number ?????????????

please help me .. its soo urgent

i 'll be back - Feb 18th 2013, 07:20 AMKmathRe: hello guysss peep in for more
- Feb 18th 2013, 08:17 AMarshiar8Re: hello guysss peep in for more

thankyou v much .. can u please clear my another doubt ????????

" there were 25 questions in an examination . each correct answer carries 2 mark and one mark will be deducted for each wrong answer. a student wrote answers for every question and got 35 marks. how many answers were correct ?"

- this is the question, please answer this also

actually my niece want answer for these question cuz of confusion .. im suffering from fever also .. my brain is not working well cuz of headache ... i dunno how im sitting in front of ma laptop ............. please answer .. dis is a request - Feb 18th 2013, 09:50 AMKmathRe: hello guysss peep in for more
I think you have to say that the student answered all the 25 questions.

Let us suppose that (the student answered all questions). Let $\displaystyle x$ be the number of correct answers so the number of wrong answer will be $\displaystyle 25-x.$

So his mark is

2* correct answer - 1* wrong answers,

since he got 35 marks, that means:

$\displaystyle 2x-(25-x)=35$

that is

$\displaystyle 2x-25-(-x)=35$

hence

$\displaystyle 2x+x-25=35$

$\displaystyle 3x-25=35$

$\displaystyle 3x=35+25$

$\displaystyle 3x=60$

$\displaystyle x=20$

So the student has 20 correct answers and 5 wrong answers,

2*20=40

-5 for the wrong answers

that is 40-5 =35!