设第一次存款是年利率为x
(100x+100-50)*(1+0.5x)=63
(100x+50)(1+0.5x)=63
100x+50x^2+50+25x=63
50x^2+125x-13=0
b^2-4ac=125^2-4*50*(-13)=188225
x1=-125+135/2*50=0.1
x2=-125-135/2*50
设第一次存款是年利率为x
(100x+100-50)*(1+0.5x)=63
(100x+50)(1+0.5x)=63
100x+50x^2+50+25x=63
50x^2+125x-13=0
b^2-4ac=125^2-4*50*(-13)=188225
x1=-125+135/2*50=0.1
x2=-125-135/2*50