If 3^x + 3^y = 3 then x + y =_______

Question

A . 0

B . -1

C.  3

D   1

Answer 1

Do you mean 3^x × 3^y = 3? If so, this is the same as 3^(x+y)=3¹, so x+y=1 which would be answer D.

[The equation 3^x + 3^y = 3 yields no simple relation between x and y. For example, if y=0, 3^x=2 and x=log₃(2) so x+y=log₃(2). If y=1, 3^x=0 and there is no solution for x (x=-∞, which is indeterminate), so x+y is indeterminate.]