Call the equations A, B and C. A + B gives 7x + 2y = -10. Call this equation D. 2B + C = 13x - 3y = -32. Call this equation E. 3D + 2E = 47x = -94, so x = -2. Substitute this value in equation D or E and we get y = 2. Substitute these values of x and y in A, B or C and we get z = -5.