(1+x)(1.02+x)=1.232
1.02+x+1.02x+x^2=1.232
2.02x+x^2=2.12
x^2+2.02+1.0201=2.12+1.0201
(x+1.01)^2=3.1401
x=正负根号3.1401-1.01