Quadratic, how to solve for R?
22.4 = (120/R+139)^2 * R
- 1 decade agoFavorite Answer
Simplify: (square the top and bottom of the fraction, then multiply top by R:
22.4 = 14400R/(R+139)^2
Clear fraction: (multiply both sides by (R+139)^2)
22.4(R+139)^2 = 14400R
Like terms/simplify: (divide both sides by 22.4 first, then subtract the result on the right onto the left side. Meanwhile, expand your squared stuff)
(R+139)^2 = 14400R/22.4
R^2 + 278R + 19321 = 642.857R
R^2 - 364.857R + 19321 = 0
Plug this equation into your graphing calculator as y=x^2 - 364.857x + 19321 in a good viewing window and then find the zeroes. The x-values = R.
Answer: R = 64.280, 300.577
Plug these back into your equation, and they both equal approximately 22.4
- Anonymous1 decade ago
im pretty sure this isn't a quadratic equation.
a quadratic equation has the format z^2*bx+c