Consider the following system of linear equations in the variables x, y, and 2: x+2y+32-7 2x-3y- 5z =9 -6x8y+z=-22 (a) Solve this system of equations algebraically (by Gaussian elimination). (b) Express the equations in the matrix form: Ma = 6, where M is the matrix of coefficients, a is the vector of unknown variables and 6 is the vector of constant terms. (c) Find the vector a by inverting the matrix M: a = M-6.