a*b = 7
a - = 4 b
a/b = 4
-5.29150262212918
-1.3228756555323
5.29150262212918
1.3228756555323
a1 = -5.291502622129181 b1 = -1.322875655532295
a2 = 5.291502622129181 b2 = 1.322875655532295