It has been quite some time since I've had to do this type of a calculation and I'm hoping that someone out there will know how to do this equation. 100 + 110/(1+r) = 1/(1+r) + 232/(1+r)2(squared)

Question

It has been quite some time since I've had to do this type of a calculation and I'm hoping that someone out there will know how to do this equation.  100 + 110/(1+r) = 1/(1+r) + 232/(1+r)2(squared)

hero · Answer

$$\frac{110}{1+r} = \frac{1}{1+r} + \frac{232}{(1+r)^2}$$

hero · Answer

Subtract 1/1+r from both sides: 

$$\frac{109}{1+r} = \frac{232}{(1+r)^2}$$

hero · Answer

Cross Multiply: 

232(1+r) = 109(1+r)^2

Continue Solving from there...

anonymous · Answer

That's my problem, I haven't done this in over 20 years, and my brain just isn't computing it.

anonymous · Answer

then 109(1+r)=232$$109r=123$$$$r=123/109$$

hero · Answer

You divided by (1+r) which is illegal when isolating r

hero · Answer

You can't cancel variables when trying to isolate them, else you eliminate a solution

hero · Answer

I ended up with r^2 - 230r-122 = 0

hero · Answer

You can solve for r from there now.

anonymous · Answer

What about the first 100?