Ta có :
TH1 :\(\left\{{}\begin{matrix}\text{ZA + ZB =32}\\\text{ZB - ZA = 8 }\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}\text{ ZA = 12}\\\text{ZB =20 }\end{matrix}\right.\)
TH2:\(\left\{{}\begin{matrix}\text{ZA + ZB = 32}\\\text{ ZB - ZA = 18 }\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}\text{ZA =7}\\\text{ZB= 25}\end{matrix}\right.\)