Solving

[reehlgirl1986]

I need to solve this but can't get it to work

(1/2x^2)+(1/3x^3)-(1/2mx)=1/12
x=-m+1
(1/2(-m+1)^2)+(1/3(-m+1)^3)-(1/2m(-m+1))=1/12
there is too many "things" in there. I get .075. I know that is not right but it should equal .12 to .2 help!

 

[stapel]

Please do not start new threads to follow up on old threads.

Thank you.

Eliz.

 

[Mrspi]

I need to solve this but can't get it to work

(1/2x^2)+(1/3x^3)-(1/2mx)=1/12
x=-m+1
(1/2(-m+1)^2)+(1/3(-m+1)^3)-(1/2m(-m+1))=1/12
there is too many "things" in there. I get .075. I know that is not right but it should equal .12 to .2 help!

Assuming you mean this:
(1/2)x² + (1/3)x³ - (1/2)mx = 1/12

Multiply both sides by the common denominator for all of the fractions, 12:
12(1/2)x² + 12(1/3)x³ - 12(1/2)mx = 12(1/12)

6x² + 4x³ - 6mx = 1

Next, you know that
x = -m + 1
Let's solve this for m:
m + x = 1
m = 1 - x

Substitute (1 - x) for m in the equation:
6x² + 4x³ - 6(1 - x)*x = 1

Now, that has a lot less "stuff" than your equation did! Solve for x, and then use the value of x to find m.