Solve \(9^x - 2 \cdot 3^x - 63 = 0\)
Solve: 9x - 2·3x - 63 = 0
Rewrite: (32)x - 2·3x - 63 = 0
32x - 2·3x - 63 = 0
Factor: (3x - 9)(3x + 7) = 0
Either: 3x = 9 ---> x = 2
or: 3x = -7 ---> (no real solution)
we get (9^x)-2*(3^x)=63 by adding 63 to both sides and then we use elimination.Finally we get x=2 so the only way for x is 2