Question

Solve the following two simultaneous equations by the method of determinants : 

4i₁ - 3i₂ = 1 

3i₁ - 5i₂ = 2

Answer 1

The matrix form of the equations is [(4, -3),(3, - 5)][i₁, i₂] = [1, 2]

Δ = |(4, - 3), (3, -5)| = (4 x - 5) - (-3 x 3) = -11

Δ₁ = |(1, -3), (2, - 5)| = (1 x - 5) - (- 3 x 2) = 1

Δ₂ = |(4, 1), (3, 2)| = (4 x 2) - (1 x 3) = 5

∴ i₁ = Δ₁/Δ = 1/-11 = - 1/11; i₂ = Δ₂/Δ = -5/11