2012 · Q95
If 3^(x+y) = 81 and 81^(x-y) = 3, then what is x equal to?
Elementary MathematicsAlgebra
- A17/16
- B17/8
- C17/4
- D15/4
Explanation
x+y = 4 and 4(x-y) = 1 give x = (4 + 1/4)/2 = 17/8.
If 3^(x+y) = 81 and 81^(x-y) = 3, then what is x equal to?
Explanation
x+y = 4 and 4(x-y) = 1 give x = (4 + 1/4)/2 = 17/8.