Friday

March 27, 2015

March 27, 2015

Posted by **mary** on Friday, April 22, 2011 at 7:55pm.

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

- algebra -
**Damon**, Friday, April 22, 2011 at 8:04pmscroll down, I answered

- algebra -
**Imagine**, Friday, April 22, 2011 at 8:05pmThe answer I got using a calc is 2

- sign error -
**Damon**, Friday, April 22, 2011 at 8:15pm(-12x+10)(-20)/5 = -x (-20/20)

I made a sign error here

48 x -40 = +x

47 x = 40

x = 40/47

- no way I get 2 -
**Damon**, Friday, April 22, 2011 at 8:16pmNot for this problem

- algebra -
**MattsRiceBowl**, Friday, April 22, 2011 at 8:39pmIs it (-12x+10) / 5

Or

-12x + (10/5)

?

- algebra -
**Damon**, Friday, April 22, 2011 at 8:51pmscroll down Matts. I did it both ways.

- algebra -
**Damon**, Friday, April 22, 2011 at 8:53pmI 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

**Answer this Question**

**Related Questions**

algebra - -12x+10/5 = - x/20 I can't decide if I should cross multiply by -20 or...

math - how do i do x2+12x+32 x2+12x = 14x+32 subtract 14x from each side 14x=32 ...

algebra - Simplify. Do not use negative exponents in the answer. 12x-2y4 -3xy-7 ...

MATH(PLease Help) - Problem: (y+2)/(y) = 1/(y-5) Directions: Solve the rational ...

5th Grade Math - I cannot get my brain around questions like this: 1/4 divided ...

algebra - how do I break this down? 4x-7 <-4 over 6 the 4x-7 is all over 6 (...

Math - The problem to solve is: (x+20)(x-12)(x+4)>0 but I can't figure out ...

Algebra - 2(3x - 7) + 4 (3 x + 2) = 6 (5 x + 9 ) + 3 how will solve it? well you...

Algebra (Re.: Reiny) - The fact that there was that nice symmetry to the ...

Algebra 1 - Rewrite the polynomial in descending order in its simplest form. ...