1.5 Lösning 5b
Från Mathonline
- \[\begin{align} (2^x + 2^{x-1}) \cdot {2 \over 3}\; & = \; 32 \qquad \; | \; \cdot {3 \over 2} \\ 2^x + 2^{x-1} & = \; 48 \\ 2^x + 2^x \cdot 2^{-1} & = \; 48 \\ 2^x \cdot (1+{1\over 2}) & = \; 48 \\ {3 \over 2} \cdot 2^x & = \; 48 \qquad \; | \; \cdot {2 \over 3}\\ 2^x & = \; 32 \\ 2^x & = \; 2^5 \\ x & = \; 5 \end{align} \]
