[(m-3)/(m+5)]^2+[(4-2m)/(m+5)]^2=1
(m-3)²+ (4-2m)² = (m+5)²
m²-6m + 9 + 16 + 4m² - 16m = m²+10m+25
4m² -32m =0
m²-8m=0
m(m-8) =0
m=0 或者 8