Thursday

August 21, 2014

August 21, 2014

Posted by **Dan** on Thursday, March 25, 2010 at 10:38pm.

solve for R.

- 4th grade math -
**drwls**, Friday, March 26, 2010 at 8:24amGee, I didn't learn any algebra until the ninth grade. What you have can be reduced to something called the quadratic equation.

2R^2 + 16R -80 = 0

R^2 +8R -40 = 0

R = (1/2)[-8 +/-sqrt224]

= 3.4833 or -11.4833

There are no integer solutions.

Are you sure you didn't mean to write

R^2 + 16R + 64 = 144 ?

That has a simpler solution that you can get by taking the square root of each side.

(R + 8)^2 = 12^2

R = -8 +or- 12 = -20 or +4

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