The figure below is an electrical circuit containing two cells of e.m.f. 
and 
.
The cells are connected to resistors of resistance 
, 
and 
and the currents in the branches of the circuit are 
, 
and 
, as shown.
Use Kirchhoff’s first law to write down an expression relating , and .
Use Kirchhoff’s second law to write down an expression relating
, , , and in the loop XBCYX,
, , , , and in the loop AXYDA,
