200x-100x^2=805x^2-10x+4=05(x-1)^2 = 1x-1 = √5/5 or -√5/5x= (5+√5)/5 or (5-√5)/5
100x2-200x=62 100x2-200x+100=162 100(x-1)2=162 (x-1)2=162/100 x-1=9√2/10或x-1=-9√2/10 x=(10+9√2)/10或x=(10-9√2)/10
