4.3.4 Example 4 (Index Equation – Substitution) January 21, 2022April 28, 2020 by Example 4Solve each of the following.(a) 3 x − 1 + 3 x = 12 (b) 2 x + 2 x + 3 = 72 (c) 4 x + 1 + 2 2 x = 20