1) 6.8^(x - 1) + 8^(x + 1) = 6.8¹⁹ + 8²¹
8^(x - 1).(6 + 8²) = 8¹⁹.(6 + 8²)
8^(x - 1) = 8¹⁹
x - 1 = 19
x = 19 + 1
x = 20
2) 5.2^x + 3.2^(x + 2) = 5.2⁵ + 3.2⁷
2^x.(5 + 3.2²) = 2⁵.(5 + 3.2²)
2^x = 2⁵
x = 5
3) 4.3^(x - 1) + 2.3^(x + 2) = 4.3⁶ + 2.3⁹
3^(x - 1).(4 + 2.3³) = 3⁶.(4 + 2.3³)
3^(x - 1) = 3⁶
x - 1 = 6
x = 6 + 1
x = 7
4) 11.6^(x - 1) + 2.6^(x + 1) = 11.6¹¹ + 2.6¹³
6^(x - 1).(11 + 2.6²) = 6¹¹.(11 + 2.6²)
6^(x - 1) = 6¹¹
x - 1 = 11
x = 11 + 1
x = 12