Solving for d_2 in a cubic denominator equation

[DB]

to solve for d_2:
$$\frac{336}{81}=\frac{175}{100}*\frac{1}{[\frac{d_2}{0.1}]^3}$$
$$\sim 2.4=\frac{1}{[\frac{d_2}{0.1}]^3}$$

then i don't know wat to do i know its simple algebra, i just don't see it,.

 

[Doc Al]

If $$a = \frac{1}{b^3}$$
Then $$b^3 = \frac{1}{a}$$

Use this idea and keep going.

 

[DB]

thnx 4 all the help doc,
i get
$$d_2=0.041^{\frac{1}{3}}$$

 

[Doc Al]

i get
$$d_2=0.041^{\frac{1}{3}}$$

That doesn't seem right. Consider the following:
$$[\frac{d_2}{0.1}]^3 = \frac{d_2^3}{0.001}$$

 

[DB]

o i see wat i did, so $$d_2=[4.1*10^{-4}]^\frac{1}{3}$$?

 

[Doc Al]

Much better.

 

[Ouabache]

Even better if you don't convert your constants to a decimal so soon.
Keep them as fractions and you should find you can easily take their cube root later.