15xx+2*14x=14^2+1/2
xx+2*14/15x=14^2/15+1/30
(x+14/15)^2=14^2/15+1/30+14^2/15^2=[14^2*15*2+15+2*14^2]/115^2=[14^2*32+15]/15^2
x=-14/15加减根号[14^2*32+15]/15
15xx+2*14x=14^2+1/2
xx+2*14/15x=14^2/15+1/30
(x+14/15)^2=14^2/15+1/30+14^2/15^2=[14^2*15*2+15+2*14^2]/115^2=[14^2*32+15]/15^2
x=-14/15加减根号[14^2*32+15]/15