(r+3.5)^2+(r+5)^2=(2r)^2 求r=?

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(r+3.5)^2+(r+5)^2=(2r)^2 求r=?

(r+3.5)^2+(r+5)^2=(2r)^2 求r=?
(r+3.5)^2+(r+5)^2=(2r)^2 求r=?

(r+3.5)^2+(r+5)^2=(2r)^2 求r=?
(r+3.5)^2+(r+5)^2=(2r)^2
(r^2 + 7r + 12.25)+ ( r^2 + 10r + 25) = 4r^2
2 r^2 - 17 r - 37.25 = 0
r = {17 ±√[17^2 - 4×2×(-37.25)]} / (2×2)
= (17 ±√587) / 4