If the number of equations is more than two, it is easier to get the solution by using determinants.

If I_{1}, I _{2} and I a are the three unknowns in a system of three linear equations

a_{11} I _{1} + a_{12}I_{2} + a_{13}I_{3} = C_{1}

a_{21}I _{1} + a_{22}I_{2} + a_{23}I_{3} = C_{2}

a_{31}I _{1} + a_{32}I_{2} + a _{33}I_{3} = C_{3}

Then, the system can be written in matrix form as follows

The values of I_{1 }and I_{2} and I_{3} are given by

This is known as Cramer’s rule and can be applied to any system of n linear equations provided Δ is not zero