Asked by mary

-12x+10/5 = - x/20
I can't decide if I should cross multiply by -20 or just 20. The - is in the middle of the x and 20 (like a fraction)
I came up with 2 possible answers:
x=40/49 and x = 40/47
Answered by Damon
scroll down, I answered
Answered by Imagine
The answer I got using a calc is 2
Answered by Damon
(-12x+10)(-20)/5 = -x (-20/20)
I made a sign error here
48 x -40 = +x
47 x = 40
x = 40/47
Answered by Damon
Not for this problem
Answered by MattsRiceBowl
Is it (-12x+10) / 5

Or
-12x + (10/5)

?
Answered by Damon
scroll down Matts. I did it both ways.
Answered by Damon
I am not a big fan of the expression "cross multiply"
What you want to do here is multiply both sides, all terms by -20 (or 20 would work too)
FIRST THE WAY YOU TYPED IT (probably wrong)
-12(-20) x + 2(-20 ) = -x(-20)
240 x - 40 = 20 x
220 x = 40
x = 2/11
NOW WHAT I THINK YOU MEAN
(-12x+10)(-20)/5 = -x (-20/20)
48 x -40 = -x
49 x = 40
x = 40/49
PARENTHESES ARE IMPORTANT WHEN TYPING EQUATION ON A COMPUTER (because of order of operations)




typo - Damon, Friday, April 22, 2011 at 8:14pm

(-12x+10)(-20)/5 = -x (-20/20)
I made a sign error here
48 x -40 = +x
47 x = 40
x = 40/47
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