aa = a
255 = 1
25255 = 1
1z5 = 0
1z1zz2z3z4 = 0
1zz2z3z4 = 0
1zz21z1z2 = 0
111z2z1z = 1zz21z1z2
solve1xx2x
152z1z152z1z = 0
22z2z15 = 0
a) solve22z2z15z
z = 152554
z = 152554
22z2z15 = 0
b) solve22z2z15z
z = 152554
z = 152554
2525 = z = 152554 = 152554
25 = 154
2a = 2a21
subst2a21a5
2521 = 154
solve25215415
5 = 2354
0.8090169943749475 = 0.8090169943749475