a R2nt (R1\\Rv)=> U= U1+u2=> U2=180-60=120V=> I2=U2\R2=120\3000=0,04A=> I1=U1\R1=60\2000=0,03A
b theo cau a ta co Iv=I2-I1=0,04-0,03=0,01A=> RV=U1\IV=60\0,01=6000 om
ta co R1nt(R2\\Rv)=>Rtd=4000 om => Imc=I1'=U\Rtd=180\4000=0,045A=>U1= I1'.R1=0,045.2000=90V => U2=U-U1=90V
cx la so chi von ke