Given 1) Z=8x' 42xy -3x3 47 +1 ii) Z = x + 2ev-ed-team ili) 2 = 8x - 2x3 +12xy -12y' + 6y iv) Z = 5x - 30* +4xy - 3y# +7y v) Z = 25 + (x -1) + (y-1) vi) Z = x' + xy +2x2+3 vii) Z =-x3 + xy -v +2x+1 viii) Z = e - 2x+2y3+3 ix) 2 = (x - 2)" + (1-3)" x) z=x- 6x2 + 23 +932-63x -60j a) Find the critical values and extreme values. b) Determine whether the extreme values are maximum, minimum or an inflection point or saddle point