Solve the system of equations using:
1. the matrix inverse. define the resulting vector for as xInv
2. matlab's built-in solvers (mldivide, \). define the resulting vector as xMAT
8x₁ + 2x₂ - 2x₃ = -2
10x₁ + 2x₂ + 4x₃ = 4
12x₁ + 2x₂ +2x₃ = 6