Yes, that's all you do. And since I made that error, the estimate I gave you last night of 0.0017 for x will be slightly lower. I have recalculated and I obtained 0.001671 and although that's too many significant figures you almost must use all of them when you check the answer to make it come out right with all of those cubed and squared terms. I checked it also and it gave me exactly 4.2E-6 for Keq so I'm comfortable with that number.
How do I factor it? I didn't. I went looking on the web for a cubic equation calculator and used that.
But you can also do it by successive iterations and I did that too. It only took two estimates. It's done this way.
Take the equation and simplify it to
4X^3 = 4.2E-6
X^3 = 0.00173 for the first estimate. Then
4.2E-6 = 4X^3/(0.07-2x)^2
Substitute that first estimate of 0.00173 (for the denominator only) and solve for X and I get 0.00167 for x.
So all I have to do now is cross multiply and solve for x right? Also when that happens, how do I factor the x^3? What do I do?
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