Consider the following problem: Maximize Z= 2x1 - x2 + x3, subject to X1 x2 + 3x3 = -4 and xi >0, x2 > 0, x3 > 0. Apply the big M method with surplus variable x4 and artificial variable is to convert this model into an appropriate form before we can apply the simplex method to solve the problem. You just need to specify the new objective function and the constraint, i.e., fill in the question mark area with the correct information: Maximize Z= ?, subject to ? and x1>0, x2 > 0, X3 > 0, X4 > 0, T5 > 0