Real numbers a and b satisfy a + ab = 250 a - ab = -240 Enter all possible values of a, separated by commas.
a + ab = 250
a - ab = -240 add these
2a = 10
a = 5
5 + 5b = 250
5b = 245
b = 245 / 5 = 49
(a, b) = (5 , 49)
+497 
