Algebra

 

Real numbers a and b satisfy    
a + ab = 250    
a - ab = -240    
Enter all possible values of a, separated by commas.    

 

 

given the two equations    

                                                     a + ab  =    250    

                                                     a – ab  =  –240    

simply add the two equations    

                                                    2a         =      10    ==>>    a = 5          

_.