please help hw

The currents I1 , I2 , Ig in a circuit with resistors R1, R2 and voltages E1 , Ez are described by the following system of equations: RI, + R, 13 = E, R,I, + R313 = E2 I1 + 12 - 13= 0 Let R1 = 2 Ohms, R2 = 1 Ohm, R3 = 4 Ohms, E, = 14 Volts and E2 = 28 Volts. 2 0 11 [14 0 12 28 A = X = 13 B = L 0 (3a) Given AX = B, find det(A). (3b) Given AX = B, find I, using Cramer's Rule