3.1     b) Determinant[{{0,0,1,3},{0,0,2,4},{1,1,sqrt(5),sqrt(7)},{1,-1,sqrt(6),sqrt(8)}}]
	c) Determinant[{{x^3+1,1,1},{1,x^3+1,1},{1,1,x^3+1}}]
        d) Determinant[{{1,2,-1,-0.002},{-3,8,0,-0.004},{2,2,-4,-0.003},{3000,8000,-1000,-6}}]
        e) Determinant[{{1001,1002,1003,1004},{1002,1003,1001,1002},{1001,1001,1001,1001},{1001,1000,998,999}}]
        f) Determinant[{{128,256,384,512},{1/4,3/8,1/8,1/4},{1/64,1/64,1/64,-1/64},{2,0,-4,-12}}]
	
3.2     a) solve x + y + 2z + 2u = 0, 2x + y + z = 4, y + u = -1
        b) solve 2x + 2y - 5z = 2, x + y + z = 1, -x -y +2z = -1
        c) solve x+2y+3z=0, 3x-5y-2z=0, x+3y+4z=0, 2x-3y-z=0, 5x+y+6z=0
        e) solve 2x + y + z + 2u = 3, 3y + z -2u = 1, 2x + 4y + 2z + 4u = 4
        f) solve x + z + 2u -v = 4, y + z + u + v = 3, x -2y -z +u -3v = 0, 2x + y + 3z + 2u -v = 5
        g) solve x + u - v = 3, x + 2y + 2z + u + 3v = 5, y + z + u + v = 1, x -3y -3z -6v = 2
        i) solve x -3y -26z +22u = 0, 3x + 8y + 24z -19u = 0, x + 2y + 4z - 3u = 0, 3x + 5y + 6z - 4u = 0
        j) solve x + 2y + 3z + u = 0, x -2y +z +u = 0, 3x -3y -7z = 0, 4y +2z +5u = 0

3.3     a) solve Determinant[{{4,-1,1},{-1,1,2},{2,1,a}}]=0
           solve 4x - y + z = 2, -x + y +2z = -2, 2x + y + 5z = 1
        b) solve Determinant[{{1,1,-1},{1,2,a-1},{1,a+1,3}}]=0
           solve x + y - z = 1, x + 2y + z = 0, x + 3y + 3z = -1
           solve x + y - z = 1, x + 2y - 3z = 0, x -y + 3z = -1
        c) solve Determinant[{{a,3,-1},{1,-1,2},{-1,1,7}}]=0
           solve -3x +3y - z = -2, x - y + 2z = 4, -x + y + 7z = 14
        d) solve Determinant[{{a,1,-1},{2,1,2},{1,-9,1}}]=0
           solve -x + y - z = 0, 2x + y + 2z = 0, x -9y + z = 0

3.4     solve x + 450 = y + 610, u + 640 = x + 310, u+600 = z + 390, y + 520 = z + 480