Question

How do I solve for b?

Answer 1

\[6bL^2 + 4 b^3 - 9 L b^2 - L^3=0\]

Answer 2

where L is a constant, b = L/4 or b=L according to wolfram but I can't do it by hand. Any ideas?

Answer 3

Any ideas Jemurray3?

Answer 4

It's not so much a matter of having ideas as just trying to factor it. The principle of the thing is the same as factoring a quadratic, it's just more involved...

Answer 5

I can't factor it though...

Answer 6

I want to solve for either b or L..

Answer 7

can't seem to do either

Answer 8

\[(4b-L)b^2 - 8Lb^2 + 6bL^2-L^3 = 0\]
\[(4b-L)b^2 - (4b-L)2bL + 4bL^2 - L^3 = 0\]
\[(4b-L)b^2 - (4b-L)2bL + (4b-L)L^2 = 0\]
\[(4b-L)(b^2-2bL-L^2) = (4b-L)(b-L)^2 = 0\]

Answer 9

Oh thanks so much jemurray!