# hello guysss peep in for more

• Feb 18th 2013, 07:03 AM
arshiar8
hello 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 ?????????????
i 'll be back
• Feb 18th 2013, 07:20 AM
Kmath
Re: hello guysss peep in for more
Quote:

Originally Posted by arshiar8
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 ?????????????
i 'll be back

Do you mean
$3x-2(x-3)=12$?

is it not equivalent to
$3x-2*x-2*-3=12$?

which is
$3x-2x+6=12$

again
$3x-2x=12-6$

that is
$x=6$
• Feb 18th 2013, 08:17 AM
arshiar8
Re: hello guysss peep in for more
Quote:

Originally Posted by Kmath
Do you mean
$3x-2(x-3)=12$?

is it not equivalent to
$3x-2*x-2*-3=12$?

which is
$3x-2x+6=12$

again
$3x-2x=12-6$

that is
$x=6$

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 ?"

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 AM
Kmath
Re: 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 $x$ be the number of correct answers so the number of wrong answer will be $25-x.$

So his mark is

since he got 35 marks, that means:

$2x-(25-x)=35$
that is
$2x-25-(-x)=35$
hence
$2x+x-25=35$
$3x-25=35$
$3x=35+25$
$3x=60$
$x=20$