4.3.4 Example 4 (Index Equation – Substitution)

Example 4
Solve each of the following.
(a)

3^{x - 1} + 3^{x} = 12

$3^{x - 1} + 3^{x} = 12$
(b)

2^{x} + 2^{x + 3} = 72

$2^{x} + 2^{x + 3} = 72$
(c)

4^{x + 1} + 2^{2 x} = 20

$4^{x + 1} + 2^{2 x} = 20$