Answer and working out

b) (9 marks)The following system of equations was obtained for the currents 11, 12 and 13 in a circuit: 211 + 13 = 4 11 +12 + 13 = 3 11 + 12 + 413 = 7 i. Write the system of equations in matrix form. ii. Either by computing the inverse, or Gaussian elimination, or Cramer's rule, find currents 11, I2 and I3