keep getting wrong answer

wrifalon

New member
Joined
Apr 22, 2008
Messages
3
2x+(6-x)/3=-3 The (6-x)/3 is a fraction (6-x) in the numerator and the 3 is on the bottom.
i get this
2x+(6/3-1/3x=-3
5/3x+6/3=-3
5/3x=-5
x=5
but that not right
what im a doing wrong
 

Denis

Senior Member
Joined
Feb 17, 2004
Messages
1,465
wrifalon said:
2x+(6-x)/3=-3
i get this
2x+(6/3-1/3x=-3 : NO! Multiply by 3 to get 6x + 6 - x = -9 (if you don't follow that, see your teacher!)
 

wrifalon

New member
Joined
Apr 22, 2008
Messages
3
the (6-x)/3 is a fraction?

the final answer is suppose tobe x=12
 

masters

Full Member
Joined
Mar 30, 2007
Messages
378
Don't think so, unless you miscopied the equation.

Start from where Denis corrected your calculations: After multiplying each term by 3, you get

6x + 6 - x = -9
Combining like terms on the left: 5x + 6 = -9
Subtracting 6 from both sides: 5x = -15
Dividing by 5: x = -3

Check:
2(-3) + (6-[sup:sv19tttr]-[/sup:sv19tttr]3)/3 = -3
-6 + 9/3 = -3
-6 + 3 = -3
-3 = -3
 

wrifalon

New member
Joined
Apr 22, 2008
Messages
3
Thanks, I understand the way you did it, the book answer must be wrong, its happen before, I dont know why they are teaching us to multiply the fraction by the reciprocal, them distribute it then do the undoing to get the answer about 20 steps when the way you did makes more sense and less steps. Thanks again
 

Subhotosh Khan

Super Moderator
Staff member
Joined
Jun 18, 2007
Messages
18,135
wrifalon said:
2x+(6-x)/3=-3 The (6-x)/3 is a fraction (6-x) in the numerator and the 3 is on the bottom.
i get this
2x+(6/3-1/3x=-3
5/3x+6/3=-3
5/3x=-5<<<<< Right after this - you went wrong

(5/3)* x * (3/5) = -5 * (3/5) <<<<< multiply by 3/5 both sides - to isolate 'x'

x = - 3

You check your answer - by putting it into the original equation:

2x + (6 - x)/3 = 2*(-3) + [6 -(-3)]/3 = -6 + 9/3 = - 6 + 3 = -3 <<<< checks
 
Top