Solve the system of equations. Write your answer in vector notation. x₁ +5x₂ + 4x₂ + 3x4 + 6x = 2 x₁ + 6x₂ +6x₂ +6x₁ +7x, = 6 x₁ +7x₂ +8x3 +10x4 +8x, = 12 x₁ +6x₂ +6x, +7x₁ +7x₁ = 8