因为并联电路电压相等,且
I2=U/R2
I1=U/R1
I2=4I1
所以R1=4R2
因为U/R1+U/R2+U/R3=7U/R1
所以U/4R2+U/R2+U/30=7U/4R2
1/4R2+1/R2+1/30=7/4R2
15+60+2R2=105
R2=15
所以R1=60,R2=15
因为并联电路电压相等,且
I2=U/R2
I1=U/R1
I2=4I1
所以R1=4R2
因为U/R1+U/R2+U/R3=7U/R1
所以U/4R2+U/R2+U/30=7U/4R2
1/4R2+1/R2+1/30=7/4R2
15+60+2R2=105
R2=15
所以R1=60,R2=15